New version 9.2

On the appveyor CI, the link of the `server` test fails with
`libmicrohttpd`.

Do not build the test on windows to not break the CI.

ChangeLog

@@ -1,3 +1,11 @@
+kiwix-lib 9.2
+=============
+
+ * Add tests
+ * Refactoring server code.
+ * [SERVER] Add HEAD, Etag and If-None-Match support.
+ * [SERVER] Compress opds catalog answers.
+
 kiwix-lib 9.1.2
 ===============
 

README.md

@@ -85,6 +85,15 @@ Meson. If you want statically linked libraries, you can add
 
 Depending of you system, `ninja` may be called `ninja-build`.
 
+Testing
+-------
+
+To run the automated tests:
+```bash
+cd build
+meson test
+```
+
 Installation
 ------------
 

android-kiwix-lib-publisher/kiwixLibAndroid/build.gradle

@@ -26,7 +26,7 @@ task writePom {
     project {
         groupId 'org.kiwix.kiwixlib'
         artifactId 'kiwixlib'
-        version '9.1.2' + (System.env.KIWIXLIB_BUILDVERSION == null ? '' : '-'+System.env.KIWIXLIB_BUILDVERSION)
+        version '9.2' + (System.env.KIWIXLIB_BUILDVERSION == null ? '' : '-'+System.env.KIWIXLIB_BUILDVERSION)
         packaging 'aar'
         name 'kiwixlib'
         url 'https://github.com/kiwix/kiwix-lib'

meson.build

@@ -1,5 +1,5 @@
 project('kiwix-lib', 'cpp',
-  version : '9.1.2', # Also change this in android-kiwix-lib-publisher/kiwixLibAndroid/build.gradle
+  version : '9.2', # Also change this in android-kiwix-lib-publisher/kiwixLibAndroid/build.gradle
   license : 'GPL',
   default_options : ['c_std=c11', 'cpp_std=c++11', 'werror=true'])
 

src/meson.build

@@ -21,6 +21,7 @@ kiwix_sources = [
   'tools/otherTools.cpp',
   'kiwixserve.cpp',
   'name_mapper.cpp',
+  'server/etag.cpp',
   'server/request_context.cpp',
   'server/response.cpp'
 ]

src/server.cpp

@@ -75,6 +75,8 @@ namespace kiwix {
 
 static IdNameMapper defaultNameMapper;
 
+typedef kainjow::mustache::data MustacheData;
+
 static int staticHandlerCallback(void* cls,
                                  struct MHD_Connection* connection,
                                  const char* url,
@@ -109,10 +111,12 @@ class InternalServer {
     bool start();
     void stop();
 
-  private:
+  private: // functions
     Response handle_request(const RequestContext& request);
     Response build_500(const std::string& msg);
     Response build_404(const RequestContext& request, const std::string& zimName);
+    Response build_304(const RequestContext& request, const ETag& etag) const;
+    Response build_redirect(const std::string& bookName, const kiwix::Entry& entry) const;
     Response build_homepage(const RequestContext& request);
     Response handle_skin(const RequestContext& request);
     Response handle_catalog(const RequestContext& request);
@@ -123,9 +127,15 @@ class InternalServer {
     Response handle_captured_external(const RequestContext& request);
     Response handle_content(const RequestContext& request);
 
-    kainjow::mustache::data get_default_data();
-    Response get_default_response();
+    MustacheData get_default_data() const;
+    MustacheData homepage_data() const;
+    Response get_default_response() const;
 
+    std::shared_ptr<Reader> get_reader(const std::string& bookName) const;
+    bool etag_not_needed(const RequestContext& r) const;
+    ETag get_matching_if_none_match_etag(const RequestContext& request) const;
+
+  private: // data
     std::string m_addr;
     int m_port;
     std::string m_root;
@@ -138,6 +148,8 @@ class InternalServer {
 
     Library* mp_library;
     NameMapper* mp_nameMapper;
+
+    std::string m_server_id;
 };
 
 
@@ -245,6 +257,8 @@ bool InternalServer::start() {
               << std::endl;
     return false;
   }
+  auto server_start_time = std::chrono::system_clock::now().time_since_epoch();
+  m_server_id = kiwix::to_string(server_start_time.count());
   return true;
 }
 
@@ -294,7 +308,8 @@ int InternalServer::handlerCallback(struct MHD_Connection* connection,
   }
   /* Unexpected method */
   if (request.get_method() != RequestMethod::GET
-   && request.get_method() != RequestMethod::POST) {
+   && request.get_method() != RequestMethod::POST
+   && request.get_method() != RequestMethod::HEAD) {
     printf("Reject request because of unhandled request method.\n");
     printf("----------------------\n");
     return MHD_NO;
@@ -311,6 +326,9 @@ int InternalServer::handlerCallback(struct MHD_Connection* connection,
     }
   }
 
+  if (response.getReturnCode() == MHD_HTTP_OK && !etag_not_needed(request))
+    response.set_server_id(m_server_id);
+
   auto ret = response.send(request, connection);
   auto end_time = std::chrono::steady_clock::now();
   auto time_span = std::chrono::duration_cast<std::chrono::duration<double>>(end_time - start_time);
@@ -321,6 +339,14 @@ int InternalServer::handlerCallback(struct MHD_Connection* connection,
   return ret;
 }
 
+Response InternalServer::build_304(const RequestContext& request, const ETag& etag) const
+{
+  auto response = get_default_response();
+  response.set_code(MHD_HTTP_NOT_MODIFIED);
+  response.set_etag(etag);
+  response.set_content("");
+  return response;
+}
 
 Response InternalServer::handle_request(const RequestContext& request)
 {
@@ -328,6 +354,10 @@ Response InternalServer::handle_request(const RequestContext& request)
     if (! request.is_valid_url())
       return build_404(request, "");
 
+    const ETag etag = get_matching_if_none_match_etag(request);
+    if ( etag )
+      return build_304(request, etag);
+
     if (kiwix::startsWith(request.get_url(), "/skin/"))
       return handle_skin(request);
 
@@ -359,14 +389,14 @@ Response InternalServer::handle_request(const RequestContext& request)
   }
 }
 
-kainjow::mustache::data InternalServer::get_default_data()
+MustacheData InternalServer::get_default_data() const
 {
-  kainjow::mustache::data data;
+  MustacheData data;
   data.set("root", m_root);
   return data;
 }
 
-Response InternalServer::get_default_response()
+Response InternalServer::get_default_response() const
 {
   return Response(m_root, m_verbose.load(), m_withTaskbar, m_withLibraryButton, m_blockExternalLinks);
 }
@@ -375,7 +405,7 @@ Response InternalServer::get_default_response()
 Response InternalServer::build_404(const RequestContext& request,
                                    const std::string& bookName)
 {
-  kainjow::mustache::data results;
+  MustacheData results;
   results.set("url", request.get_full_url());
 
   auto response = get_default_response();
@@ -390,7 +420,7 @@ Response InternalServer::build_404(const RequestContext& request,
 
 Response InternalServer::build_500(const std::string& msg)
 {
-  kainjow::mustache::data data;
+  MustacheData data;
   data.set("error", msg);
   Response response(m_root, true, false, false, false);
   response.set_template(RESOURCE::templates::_500_html, data);
@@ -399,15 +429,15 @@ Response InternalServer::build_500(const std::string& msg)
   return response;
 }
 
-Response InternalServer::build_homepage(const RequestContext& request)
+MustacheData InternalServer::homepage_data() const
 {
   auto data = get_default_data();
 
-  kainjow::mustache::data books{kainjow::mustache::data::type::list};
+  MustacheData books{MustacheData::type::list};
   for (auto& bookId: mp_library->filter(kiwix::Filter().local(true).valid(true))) {
     auto& currentBook = mp_library->getBookById(bookId);
 
-    kainjow::mustache::data book;
+    MustacheData book;
     book.set("name", mp_nameMapper->getNameForId(bookId));
     book.set("title", currentBook.getTitle());
     book.set("description", currentBook.getDescription());
@@ -417,9 +447,34 @@ Response InternalServer::build_homepage(const RequestContext& request)
   }
 
   data.set("books", books);
+  return data;
+}
 
+bool InternalServer::etag_not_needed(const RequestContext& request) const
+{
+  const std::string url = request.get_url();
+  return kiwix::startsWith(url, "/catalog")
+      || url == "/search"
+      || url == "/suggest"
+      || url == "/random"
+      || url == "/catch/external";
+}
+
+ETag
+InternalServer::get_matching_if_none_match_etag(const RequestContext& r) const
+{
+  try {
+    const std::string etag_list = r.get_header(MHD_HTTP_HEADER_IF_NONE_MATCH);
+    return ETag::match(etag_list, m_server_id);
+  } catch (const std::out_of_range&) {
+    return ETag();
+  }
+}
+
+Response InternalServer::build_homepage(const RequestContext& request)
+{
   auto response = get_default_response();
-  response.set_template(RESOURCE::templates::index_html, data);
+  response.set_template(RESOURCE::templates::index_html, homepage_data());
   response.set_mimeType("text/html; charset=utf-8");
   response.set_compress(true);
   response.set_taskbar("", "");
@@ -474,7 +529,7 @@ Response InternalServer::handle_meta(const RequestContext& request)
   response.set_content(content);
   response.set_mimeType(mimeType);
   response.set_compress(false);
-  response.set_cache(true);
+  response.set_cacheable();
   return response;
 }
 
@@ -507,14 +562,14 @@ Response InternalServer::handle_suggest(const RequestContext& request)
     printf("Searching suggestions for: \"%s\"\n", term.c_str());
   }
 
-  kainjow::mustache::data results{kainjow::mustache::data::type::list};
+  MustacheData results{MustacheData::type::list};
 
   bool first = true;
   if (reader != nullptr) {
     /* Get the suggestions */
     reader->searchSuggestionsSmart(term, maxSuggestionCount);
     while (reader->getNextSuggestion(suggestion)) {
-      kainjow::mustache::data result;
+      MustacheData result;
       result.set("label", suggestion);
       result.set("value", suggestion);
       result.set("first", first);
@@ -526,7 +581,7 @@ Response InternalServer::handle_suggest(const RequestContext& request)
 
   /* Propose the fulltext search if possible */
   if (reader->hasFulltextIndex()) {
-    kainjow::mustache::data result;
+    MustacheData result;
     result.set("label", "containing '" + term + "'...");
     result.set("value", term + " ");
     result.set("first", first);
@@ -558,7 +613,7 @@ Response InternalServer::handle_skin(const RequestContext& request)
   }
   response.set_mimeType(getMimeTypeForFile(resourceName));
   response.set_compress(true);
-  response.set_cache(true);
+  response.set_cacheable();
   return response;
 }
 
@@ -711,10 +766,7 @@ Response InternalServer::handle_random(const RequestContext& request)
 
   try {
     auto entry = reader->getRandomPage();
-    entry = entry.getFinalEntry();
-    auto response = get_default_response();
-    response.set_redirection(m_root + "/" + bookName + "/" + kiwix::urlEncode(entry.getPath()));
-    return response;
+    return build_redirect(bookName, entry.getFinalEntry());
   } catch(kiwix::NoEntry& e) {
     return build_404(request, bookName);
   }
@@ -772,7 +824,7 @@ Response InternalServer::handle_catalog(const RequestContext& request)
   opdsDumper.setRootLocation(m_root);
   opdsDumper.setSearchDescriptionUrl("catalog/searchdescription.xml");
   opdsDumper.setLibrary(mp_library);
-  response.set_mimeType("application/atom+xml;profile=opds-catalog;kind=acquisition; charset=utf-8");
+  response.set_mimeType("application/atom+xml; profile=opds-catalog; kind=acquisition; charset=utf-8");
   std::vector<std::string> bookIdsToDump;
   if (url == "root.xml") {
     opdsDumper.setTitle("All zims");
@@ -824,36 +876,52 @@ Response InternalServer::handle_catalog(const RequestContext& request)
   return response;
 }
 
+namespace
+{
+
+std::string get_book_name(const RequestContext& request)
+{
+  try {
+    return request.get_url_part(0);
+  } catch (const std::out_of_range& e) {
+    return std::string();
+  }
+}
+
+} // unnamed namespace
+
+std::shared_ptr<Reader>
+InternalServer::get_reader(const std::string& bookName) const
+{
+  std::shared_ptr<Reader> reader;
+  try {
+    const std::string bookId = mp_nameMapper->getIdForName(bookName);
+    reader = mp_library->getReaderById(bookId);
+  } catch (const std::out_of_range& e) {
+  }
+  return reader;
+}
+
+Response
+InternalServer::build_redirect(const std::string& bookName, const kiwix::Entry& entry) const
+{
+  auto response = get_default_response();
+  response.set_redirection(m_root + "/" + bookName + "/" +
+                           kiwix::urlEncode(entry.getPath()));
+  return response;
+}
+
 Response InternalServer::handle_content(const RequestContext& request)
 {
   if (m_verbose.load()) {
     printf("** running handle_content\n");
   }
 
-  std::string baseUrl;
-  std::string content;
-  std::string mimeType;
-
-  kiwix::Entry entry;
-
-  std::string bookName;
-  try {
-    bookName = request.get_url_part(0);
-  } catch (const std::out_of_range& e) {
-    return build_homepage(request);
-  }
+  const std::string bookName = get_book_name(request);
   if (bookName.empty())
     return build_homepage(request);
 
-  std::string bookId;
-  std::shared_ptr<Reader> reader;
-  try {
-    bookId = mp_nameMapper->getIdForName(bookName);
-    reader = mp_library->getReaderById(bookId);
-  } catch (const std::out_of_range& e) {
-    return build_404(request, bookName);
-  }
-
+  const std::shared_ptr<Reader> reader = get_reader(bookName);
   if (reader == nullptr) {
     return build_404(request, bookName);
   }
@@ -863,16 +931,14 @@ Response InternalServer::handle_content(const RequestContext& request)
     urlStr = urlStr.substr(1);
   }
 
+  kiwix::Entry entry;
+
   try {
     entry = reader->getEntryFromPath(urlStr);
     if (entry.isRedirect() || urlStr.empty()) {
       // If urlStr is empty, we want to mainPage.
       // We must do a redirection to the real page.
-      entry = entry.getFinalEntry();
-      auto response = get_default_response();
-      response.set_redirection(m_root + "/" + bookName + "/" +
-        kiwix::urlEncode(entry.getPath()));
-      return response;
+      return build_redirect(bookName, entry.getFinalEntry());
     }
   } catch(kiwix::NoEntry& e) {
     if (m_verbose.load())
@@ -881,47 +947,19 @@ Response InternalServer::handle_content(const RequestContext& request)
     return build_404(request, bookName);
   }
 
-  try {
-    mimeType = entry.getMimetype();
-  } catch (exception& e) {
-    mimeType = "application/octet-stream";
-  }
+  auto response = get_default_response();
+
+  response.set_entry(entry, request);
 
   if (m_verbose.load()) {
-    printf("Found %s\n", urlStr.c_str());
-    printf("mimeType: %s\n", mimeType.c_str());
+    printf("Found %s\n", entry.getPath().c_str());
+    printf("mimeType: %s\n", response.get_mimeType().c_str());
   }
 
-  if (mimeType.find("text/") != string::npos
-      || mimeType.find("application/javascript") != string::npos
-      || mimeType.find("application/json") != string::npos) {
-    zim::Blob raw_content = entry.getBlob();
-    content = string(raw_content.data(), raw_content.size());
-    auto response = get_default_response();
+  if (response.get_mimeType().find("text/html") != string::npos)
+    response.set_taskbar(bookName, reader->getTitle());
 
-    if (mimeType.find("text/html") != string::npos)
-      response.set_taskbar(bookName, reader->getTitle());
-
-    response.set_mimeType(mimeType);
-    response.set_content(content);
-    response.set_compress(true);
-    response.set_cache(true);
-    return response;
-  } else {
-    int range_len;
-    if (request.get_range().second == -1) {
-       range_len = entry.getSize() - request.get_range().first;
-    } else {
-       range_len = request.get_range().second - request.get_range().first;
-    }
-    auto response = get_default_response();
-    response.set_entry(entry);
-    response.set_mimeType(mimeType);
-    response.set_range_first(request.get_range().first);
-    response.set_range_len(range_len);
-    response.set_cache(true);
-    return response;
-  }
+  return response;
 }
 
 }

src/server/etag.cpp

@@ -0,0 +1,135 @@
+/*
+ * Copyright 2020 Veloman Yunkan <veloman.yunkan@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU  General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+
+#include "etag.h"
+
+#include "tools/stringTools.h"
+
+#include <algorithm>
+#include <sstream>
+
+namespace kiwix {
+
+namespace {
+
+// Characters in the options part of the ETag could in principle be picked up
+// from the latin alphabet in natural order (the character corresponding to
+// ETag::Option opt would be 'a'+opt; that would somewhat simplify the code in
+// this file). However it is better to have some mnemonics in the option names,
+// hence below variable: all_options[opt] corresponds to the character going
+// into the ETag for ETag::Option opt.
+// IMPORTANT: The characters in all_options must come in sorted order (so that
+// IMPORTANT: isValidOptionsString() works correctly).
+const char all_options[] = "cz";
+
+static_assert(ETag::OPTION_COUNT == sizeof(all_options) - 1, "");
+
+bool isValidServerId(const std::string& s)
+{
+  return !s.empty() && s.find_first_of("\"/") == std::string::npos;
+}
+
+bool isSubsequenceOf(const std::string& s, const std::string& sortedString)
+{
+  std::string::size_type i = 0;
+  for ( const char c : s )
+  {
+    const std::string::size_type j = sortedString.find(c, i);
+    if ( j == std::string::npos )
+      return false;
+    i = j+1;
+  }
+  return true;
+}
+
+bool isValidOptionsString(const std::string& s)
+{
+  return isSubsequenceOf(s, all_options);
+}
+
+} // namespace
+
+
+void ETag::set_option(Option opt)
+{
+  if ( ! get_option(opt) )
+  {
+    m_options.push_back(all_options[opt]);
+    std::sort(m_options.begin(), m_options.end());
+  }
+}
+
+bool ETag::get_option(Option opt) const
+{
+  return m_options.find(all_options[opt]) != std::string::npos;
+}
+
+std::string ETag::get_etag() const
+{
+  if ( m_serverId.empty() )
+    return std::string();
+
+  return "\"" + m_serverId + "/" + m_options + "\"";
+}
+
+ETag::ETag(const std::string& serverId, const std::string& options)
+{
+  if ( isValidServerId(serverId) && isValidOptionsString(options) )
+  {
+    m_serverId = serverId;
+    m_options = options;
+  }
+}
+
+ETag ETag::parse(std::string s)
+{
+  if ( kiwix::startsWith("W/", s) )
+    s = s.substr(2);
+
+  if ( s.front() != '"' || s.back() != '"' )
+    return ETag();
+
+  s = s.substr(1, s.size()-2);
+
+  const std::string::size_type i = s.find('/');
+  if ( i == std::string::npos )
+    return ETag();
+
+  return ETag(s.substr(0, i), s.substr(i+1));
+}
+
+ETag ETag::match(const std::string& etags, const std::string& server_id)
+{
+  std::istringstream ss(etags);
+  std::string etag_str;
+  while ( ss >> etag_str )
+  {
+    if ( etag_str.back() == ',' )
+      etag_str.pop_back();
+
+    const ETag etag = parse(etag_str);
+    if ( etag && etag.m_serverId == server_id )
+      return etag;
+  }
+
+  return ETag();
+}
+
+} // namespace kiwix

src/server/etag.h

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2020 Veloman Yunkan <veloman.yunkan@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU  General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+
+#ifndef KIWIXLIB_SERVER_ETAG_H
+#define KIWIXLIB_SERVER_ETAG_H
+
+#include <string>
+
+namespace kiwix {
+
+// The ETag string used by Kiwix server (more precisely, its value inside the
+// double quotes) consists of two parts:
+//
+// 1. ServerId - The string obtained on server start up
+//
+// 2. Options -  Zero or more characters encoding the values of some of the
+//               headers of the response
+//
+// The two parts are separated with a slash (/) symbol (which is always present,
+// even when the the options part is empty). Neither portion of a Kiwix ETag
+// may contain the slash symbol.
+// Examples of valid Kiwix server ETags (including the double quotes):
+//
+//   "abcdefghijklmn/"
+//   "1234567890/z"
+//   "1234567890/cz"
+//
+// The options part of the Kiwix ETag allows to correctly set the required
+// headers when responding to a conditional If-None-Match request with a 304
+// (Not Modified) response without following the full code path that would
+// discover the necessary options.
+
+class ETag
+{
+  public: // types
+    enum Option {
+      CACHEABLE_ENTITY,
+      COMPRESSED_CONTENT,
+      OPTION_COUNT
+    };
+
+  public: // functions
+    ETag() {}
+
+    void set_server_id(const std::string& id) { m_serverId = id; }
+    void set_option(Option opt);
+
+    explicit operator bool() const { return !m_serverId.empty(); }
+
+    bool get_option(Option opt) const;
+    std::string get_etag() const;
+
+
+    static ETag match(const std::string& etags, const std::string& server_id);
+
+  private: // functions
+    ETag(const std::string& serverId, const std::string& options);
+
+    static ETag parse(std::string s);
+
+  private: // data
+    std::string m_serverId;
+    std::string m_options;
+};
+
+} // namespace kiwix
+
+#endif // KIWIXLIB_SERVER_ETAG_H

src/server/request_context.cpp

@@ -30,60 +30,56 @@ namespace kiwix {
 
 static std::atomic_ullong s_requestIndex(0);
 
+namespace {
+
+RequestMethod str2RequestMethod(const std::string& method) {
+  if      (method == "GET")     return RequestMethod::GET;
+  else if (method == "HEAD")    return RequestMethod::HEAD;
+  else if (method == "POST")    return RequestMethod::POST;
+  else if (method == "PUT")     return RequestMethod::PUT;
+  else if (method == "DELETE")  return RequestMethod::DELETE_;
+  else if (method == "CONNECT") return RequestMethod::CONNECT;
+  else if (method == "OPTIONS") return RequestMethod::OPTIONS;
+  else if (method == "TRACE")   return RequestMethod::TRACE;
+  else if (method == "PATCH")   return RequestMethod::PATCH;
+  else                          return RequestMethod::OTHER;
+}
+
+std::string
+fullURL2LocalURL(const std::string& full_url, const std::string& rootLocation)
+{
+  if (rootLocation.empty()) {
+    // nothing special to handle.
+    return full_url;
+  } else if (full_url == rootLocation) {
+    return "/";
+  } else if (full_url.size() > rootLocation.size() &&
+             full_url.substr(0, rootLocation.size()+1) == rootLocation + "/") {
+    return full_url.substr(rootLocation.size());
+  } else {
+    return "";
+  }
+}
+
+} // unnamed namespace
+
 RequestContext::RequestContext(struct MHD_Connection* connection,
                                std::string rootLocation,
                                const std::string& _url,
-                               const std::string& method,
+                               const std::string& _method,
                                const std::string& version) :
   full_url(_url),
-  url(_url),
-  valid_url(true),
+  url(fullURL2LocalURL(_url, rootLocation)),
+  method(str2RequestMethod(_method)),
   version(version),
   requestIndex(s_requestIndex++),
   acceptEncodingDeflate(false),
   accept_range(false),
   range_pair(0, -1)
 {
-  if (method == "GET") {
-    this->method = RequestMethod::GET;
-  } else if (method == "HEAD") {
-    this->method = RequestMethod::HEAD;
-  } else if (method == "POST") {
-    this->method = RequestMethod::POST;
-  } else if (method == "PUT") {
-    this->method = RequestMethod::PUT;
-  } else if (method == "DELETE") {
-    this->method = RequestMethod::DELETE_;
-  } else if (method == "CONNECT") {
-    this->method = RequestMethod::CONNECT;
-  } else if (method == "OPTIONS") {
-    this->method = RequestMethod::OPTIONS;
-  } else if (method == "TRACE") {
-    this->method = RequestMethod::TRACE;
-  } else if (method == "PATCH") {
-    this->method = RequestMethod::PATCH;
-  } else {
-    this->method = RequestMethod::OTHER;
-  }
-
   MHD_get_connection_values(connection, MHD_HEADER_KIND, &RequestContext::fill_header, this);
   MHD_get_connection_values(connection, MHD_GET_ARGUMENT_KIND, &RequestContext::fill_argument, this);
 
-  valid_url = true;
-  if (rootLocation.empty()) {
-    // nothing special to handle.
-    url = full_url;
-  } else {
-    if (full_url == rootLocation) {
-      url = "/";
-    } else if (full_url.size() > rootLocation.size() &&
-               full_url.substr(0, rootLocation.size()+1) == rootLocation + "/") {
-      url = full_url.substr(rootLocation.size());
-    } else {
-      valid_url = false;
-    }
-  }
-
   try {
     acceptEncodingDeflate =
         (get_header(MHD_HTTP_HEADER_ACCEPT_ENCODING).find("deflate") != std::string::npos);
@@ -147,10 +143,11 @@ void RequestContext::print_debug_info() const {
     printf(" - %s : '%s'\n", it->first.c_str(), it->second.c_str());
   }
   printf("Parsed : \n");
+  printf("full_url: %s\n", full_url.c_str());
   printf("url   : %s\n", url.c_str());
   printf("acceptEncodingDeflate : %d\n", acceptEncodingDeflate);
   printf("has_range : %d\n", accept_range);
-  printf("is_valid_url : %d\n", valid_url);
+  printf("is_valid_url : %d\n", is_valid_url());
   printf(".............\n");
 }
 
@@ -188,7 +185,7 @@ std::string RequestContext::get_full_url() const {
 }
 
 bool RequestContext::is_valid_url() const {
-  return valid_url;
+  return !url.empty();
 }
 
 bool RequestContext::has_range() const {

src/server/request_context.h

@@ -51,7 +51,10 @@ class IndexError: public std::runtime_error {};
 
 
 class RequestContext {
-  public:
+  public: // types
+  typedef std::pair<int, int> ByteRange;
+
+  public: // functions
     RequestContext(struct MHD_Connection* connection,
                    std::string rootLocation,
                    const std::string& url,
@@ -79,14 +82,13 @@ class RequestContext {
     std::string get_full_url() const;
 
     bool has_range() const;
-    std::pair<int, int> get_range() const;
+    ByteRange get_range() const;
 
     bool can_compress() const { return acceptEncodingDeflate; }
 
-  private:
+  private: // data
     std::string full_url;
     std::string url;
-    bool valid_url;
     RequestMethod method;
     std::string version;
     unsigned long long requestIndex;
@@ -94,10 +96,11 @@ class RequestContext {
     bool acceptEncodingDeflate;
 
     bool accept_range;
-    std::pair<int, int> range_pair;
+    ByteRange range_pair;
     std::map<std::string, std::string> headers;
     std::map<std::string, std::string> arguments;
 
+  private: // functions
     static int fill_header(void *, enum MHD_ValueKind, const char*, const char*);
     static int fill_argument(void *, enum MHD_ValueKind, const char*, const char*);
 };

src/server/response.cpp

@@ -17,6 +17,37 @@
 
 namespace kiwix {
 
+namespace
+{
+// some utilities
+
+std::string get_mime_type(const kiwix::Entry& entry)
+{
+  try {
+    return entry.getMimetype();
+  } catch (exception& e) {
+    return "application/octet-stream";
+  }
+}
+
+bool is_compressible_mime_type(const std::string& mimeType)
+{
+  return mimeType.find("text/") != string::npos
+      || mimeType.find("application/javascript") != string::npos
+      || mimeType.find("application/atom") != string::npos
+      || mimeType.find("application/opensearchdescription") != string::npos
+      || mimeType.find("application/json") != string::npos;
+}
+
+int get_range_len(const kiwix::Entry& entry, RequestContext::ByteRange range)
+{
+  return range.second == -1
+       ? entry.getSize() - range.first
+       : range.second - range.first;
+}
+
+} // unnamed namespace
+
 Response::Response(const std::string& root, bool verbose, bool withTaskbar, bool withLibraryButton, bool blockExternalLinks)
   : m_verbose(verbose),
     m_root(root),
@@ -26,7 +57,6 @@ Response::Response(const std::string& root, bool verbose, bool withTaskbar, bool
     m_withTaskbar(withTaskbar),
     m_withLibraryButton(withLibraryButton),
     m_blockExternalLinks(blockExternalLinks),
-    m_useCache(false),
     m_addTaskbar(false),
     m_bookName(""),
     m_startRange(0),
@@ -139,89 +169,123 @@ void Response::inject_externallinks_blocker()
     script_tag);
 }
 
-
-int Response::send(const RequestContext& request, MHD_Connection* connection)
+bool
+Response::can_compress(const RequestContext& request) const
 {
-  MHD_Response* response = nullptr;
-  switch (m_mode) {
-    case ResponseMode::RAW_CONTENT : {
-      if (m_addTaskbar) {
-        introduce_taskbar();
-      }
-      if ( m_blockExternalLinks ) {
-        inject_externallinks_blocker();
-      }
+  return request.can_compress()
+      && is_compressible_mime_type(m_mimeType)
+      && (m_content.size() > KIWIX_MIN_CONTENT_SIZE_TO_DEFLATE);
+}
 
-      bool shouldCompress = m_compress && request.can_compress();
-      shouldCompress &= m_mimeType.find("text/") != string::npos
-                     || m_mimeType.find("application/javascript") != string::npos
-                     || m_mimeType.find("application/json") != string::npos;
+MHD_Response*
+Response::create_raw_content_mhd_response(const RequestContext& request)
+{
+  if (m_addTaskbar) {
+    introduce_taskbar();
+  }
+  if ( m_blockExternalLinks ) {
+    inject_externallinks_blocker();
+  }
 
-      shouldCompress &= (m_content.size() > KIWIX_MIN_CONTENT_SIZE_TO_DEFLATE);
-
-      if (shouldCompress) {
-        std::vector<Bytef> compr_buffer(compressBound(m_content.size()));
-        uLongf comprLen = compr_buffer.capacity();
-        int err = compress(&compr_buffer[0],
-                           &comprLen,
-                           (const Bytef*)(m_content.data()),
-                           m_content.size());
-        if (err == Z_OK && comprLen > 2 && comprLen < (m_content.size() + 2)) {
-          /* /!\ Internet Explorer has a bug with deflate compression.
-             It can not handle the first two bytes (compression headers)
-             We need to chunk them off (move the content 2bytes)
-             It has no incidence on other browsers
-             See http://www.subbu.org/blog/2008/03/ie7-deflate-or-not and comments */
-          m_content = string((char*)&compr_buffer[2], comprLen - 2);
-        } else {
-          shouldCompress = false;
-        }
-      }
-
-      response = MHD_create_response_from_buffer(
-        m_content.size(), const_cast<char*>(m_content.data()), MHD_RESPMEM_MUST_COPY);
-
-      if (shouldCompress) {
-        MHD_add_response_header(
-            response, MHD_HTTP_HEADER_VARY, "Accept-Encoding");
-        MHD_add_response_header(
-            response, MHD_HTTP_HEADER_CONTENT_ENCODING, "deflate");
-      }
-      MHD_add_response_header(response, MHD_HTTP_HEADER_CONTENT_TYPE, m_mimeType.c_str());
-      break;
-    }
-
-    case ResponseMode::REDIRECTION : {
-      response = MHD_create_response_from_buffer(0, nullptr, MHD_RESPMEM_MUST_COPY);
-      MHD_add_response_header(response, MHD_HTTP_HEADER_LOCATION, m_content.c_str());
-      break;
-    }
-
-    case ResponseMode::ENTRY : {
-      response = MHD_create_response_from_callback(m_entry.getSize(),
-                                                   16384,
-                                                   callback_reader_from_entry,
-                                                   new RunningResponse(m_entry, m_startRange),
-                                                   callback_free_response);
-      MHD_add_response_header(response,
-        MHD_HTTP_HEADER_CONTENT_TYPE, m_mimeType.c_str());
-      MHD_add_response_header(response, MHD_HTTP_HEADER_ACCEPT_RANGES, "bytes");
-      std::ostringstream oss;
-      oss << "bytes " << m_startRange << "-" << m_startRange + m_lenRange - 1
-          << "/" << m_entry.getSize();
-
-      MHD_add_response_header(response,
-        MHD_HTTP_HEADER_CONTENT_RANGE, oss.str().c_str());
-
-      MHD_add_response_header(response,
-        MHD_HTTP_HEADER_CONTENT_LENGTH, kiwix::to_string(m_lenRange).c_str());
-      break;
+  bool shouldCompress = m_compress && can_compress(request);
+  if (shouldCompress) {
+    std::vector<Bytef> compr_buffer(compressBound(m_content.size()));
+    uLongf comprLen = compr_buffer.capacity();
+    int err = compress(&compr_buffer[0],
+                       &comprLen,
+                       (const Bytef*)(m_content.data()),
+                       m_content.size());
+    if (err == Z_OK && comprLen > 2 && comprLen < (m_content.size() + 2)) {
+      /* /!\ Internet Explorer has a bug with deflate compression.
+         It can not handle the first two bytes (compression headers)
+         We need to chunk them off (move the content 2bytes)
+         It has no incidence on other browsers
+         See http://www.subbu.org/blog/2008/03/ie7-deflate-or-not and comments */
+      m_content = string((char*)&compr_buffer[2], comprLen - 2);
+      m_etag.set_option(ETag::COMPRESSED_CONTENT);
+    } else {
+      shouldCompress = false;
     }
   }
 
+  MHD_Response* response = MHD_create_response_from_buffer(
+    m_content.size(), const_cast<char*>(m_content.data()), MHD_RESPMEM_MUST_COPY);
+
+  // At shis point m_etag.get_option(ETag::COMPRESSED_CONTENT) and
+  // shouldCompress can have different values. This can happen for a 304 (Not
+  // Modified) response generated while handling a conditional If-None-Match
+  // request. In that case the m_etag (together with its COMPRESSED_CONTENT
+  // option) is obtained from the ETag list of the If-None-Match header and the
+  // response has no body (which shouldn't be compressed).
+  if ( m_etag.get_option(ETag::COMPRESSED_CONTENT) ) {
+    MHD_add_response_header(
+        response, MHD_HTTP_HEADER_VARY, "Accept-Encoding");
+  }
+  if (shouldCompress) {
+    MHD_add_response_header(
+        response, MHD_HTTP_HEADER_CONTENT_ENCODING, "deflate");
+  }
+  MHD_add_response_header(response, MHD_HTTP_HEADER_CONTENT_TYPE, m_mimeType.c_str());
+  return response;
+}
+
+MHD_Response*
+Response::create_redirection_mhd_response() const
+{
+  MHD_Response* response = MHD_create_response_from_buffer(0, nullptr, MHD_RESPMEM_MUST_COPY);
+  MHD_add_response_header(response, MHD_HTTP_HEADER_LOCATION, m_content.c_str());
+  return response;
+}
+
+MHD_Response*
+Response::create_entry_mhd_response() const
+{
+  MHD_Response* response = MHD_create_response_from_callback(m_entry.getSize(),
+                                               16384,
+                                               callback_reader_from_entry,
+                                               new RunningResponse(m_entry, m_startRange),
+                                               callback_free_response);
+  MHD_add_response_header(response,
+    MHD_HTTP_HEADER_CONTENT_TYPE, m_mimeType.c_str());
+  MHD_add_response_header(response, MHD_HTTP_HEADER_ACCEPT_RANGES, "bytes");
+  std::ostringstream oss;
+  oss << "bytes " << m_startRange << "-" << m_startRange + m_lenRange - 1
+      << "/" << m_entry.getSize();
+
+  MHD_add_response_header(response,
+    MHD_HTTP_HEADER_CONTENT_RANGE, oss.str().c_str());
+
+  MHD_add_response_header(response,
+    MHD_HTTP_HEADER_CONTENT_LENGTH, kiwix::to_string(m_lenRange).c_str());
+  return response;
+}
+
+MHD_Response*
+Response::create_mhd_response(const RequestContext& request)
+{
+  switch (m_mode) {
+    case ResponseMode::RAW_CONTENT :
+      return create_raw_content_mhd_response(request);
+
+    case ResponseMode::REDIRECTION :
+      return create_redirection_mhd_response();
+
+    case ResponseMode::ENTRY :
+      return create_entry_mhd_response();
+  }
+  return nullptr;
+}
+
+int Response::send(const RequestContext& request, MHD_Connection* connection)
+{
+  MHD_Response* response = create_mhd_response(request);
+
   MHD_add_response_header(response, "Access-Control-Allow-Origin", "*");
   MHD_add_response_header(response, MHD_HTTP_HEADER_CACHE_CONTROL,
-    m_useCache ? "max-age=2723040, public" : "no-cache, no-store, must-revalidate");
+    m_etag.get_option(ETag::CACHEABLE_ENTITY) ? "max-age=2723040, public" : "no-cache, no-store, must-revalidate");
+  const std::string etag = m_etag.get_etag();
+  if ( ! etag.empty() )
+      MHD_add_response_header(response, MHD_HTTP_HEADER_ETAG, etag.c_str());
 
   if (m_returnCode == MHD_HTTP_OK && request.has_range())
     m_returnCode = MHD_HTTP_PARTIAL_CONTENT;
@@ -249,9 +313,25 @@ void Response::set_redirection(const std::string& url) {
   m_returnCode = MHD_HTTP_FOUND;
 }
 
-void Response::set_entry(const Entry& entry) {
+void Response::set_entry(const Entry& entry, const RequestContext& request) {
   m_entry = entry;
   m_mode = ResponseMode::ENTRY;
+
+  const std::string mimeType = get_mime_type(entry);
+  set_mimeType(mimeType);
+  set_cacheable();
+
+  if ( is_compressible_mime_type(mimeType) ) {
+    zim::Blob raw_content = entry.getBlob();
+    const std::string content = string(raw_content.data(), raw_content.size());
+
+    set_content(content);
+    set_compress(true);
+  } else {
+    const int range_len = get_range_len(entry, request.get_range());
+    set_range_first(request.get_range().first);
+    set_range_len(range_len);
+  }
 }
 
 void Response::set_taskbar(const std::string& bookName, const std::string& bookTitle)

src/server/response.h

@@ -25,6 +25,7 @@
 
 #include <mustache.hpp>
 #include "entry.h"
+#include "etag.h"
 
 extern "C" {
 #include <microhttpd.h>
@@ -50,23 +51,34 @@ class Response {
     void set_template(const std::string& template_str, kainjow::mustache::data data);
     void set_content(const std::string& content);
     void set_redirection(const std::string& url);
-    void set_entry(const Entry& entry);
+    void set_entry(const Entry& entry, const RequestContext& request);
 
 
     void set_mimeType(const std::string& mimeType) { m_mimeType = mimeType; }
     void set_code(int code) { m_returnCode = code; }
-    void set_cache(bool cache) { m_useCache = cache; }
+    void set_cacheable() { m_etag.set_option(ETag::CACHEABLE_ENTITY); }
+    void set_server_id(const std::string& id) { m_etag.set_server_id(id); }
+    void set_etag(const ETag& etag) { m_etag = etag; }
     void set_compress(bool compress) { m_compress = compress; }
     void set_taskbar(const std::string& bookName, const std::string& bookTitle);
     void set_range_first(uint64_t start) { m_startRange = start; }
     void set_range_len(uint64_t len) { m_lenRange = len; }
 
-    int getReturnCode() { return m_returnCode; }
+    int getReturnCode() const { return m_returnCode; }
+    std::string get_mimeType() const { return m_mimeType; }
 
     void introduce_taskbar();
     void inject_externallinks_blocker();
 
-  private:
+    bool can_compress(const RequestContext& request) const;
+
+  private: // functions
+    MHD_Response* create_mhd_response(const RequestContext& request);
+    MHD_Response* create_raw_content_mhd_response(const RequestContext& request);
+    MHD_Response* create_redirection_mhd_response() const;
+    MHD_Response* create_entry_mhd_response() const;
+
+  private: // data
     bool m_verbose;
     ResponseMode m_mode;
     std::string m_root;
@@ -77,13 +89,13 @@ class Response {
     bool m_withTaskbar;
     bool m_withLibraryButton;
     bool m_blockExternalLinks;
-    bool m_useCache;
     bool m_compress;
     bool m_addTaskbar;
     std::string m_bookName;
     std::string m_bookTitle;
     uint64_t m_startRange;
     uint64_t m_lenRange;
+    ETag m_etag;
 };
 
 }

static/meson.build

@@ -1,3 +1,8 @@
+resource_files = run_command(find_program('python3'),
+                    '-c',
+                    'import sys; f=open(sys.argv[1]); print(f.read())',
+                    files('resources_list.txt')
+                 ).stdout().strip().split('\n')
 
 lib_resources = custom_target('resources',
     input: 'resources_list.txt',
@@ -7,5 +12,5 @@ lib_resources = custom_target('resources',
              '--hfile', '@OUTPUT1@',
              '--source_dir', '@OUTDIR@',
              '@INPUT@'],
-    build_always_stale: true
+    depend_files: resource_files
 )

test/manager.cpp

@@ -0,0 +1,25 @@
+#include "gtest/gtest.h"
+#include "../include/manager.h"
+#include "../include/library.h"
+#include "../include/book.h"
+#include <iostream>
+#include <fstream>
+
+TEST(ManagerTest, addBookFromPathAndGetIdTest)
+{
+    kiwix::Library lib;
+    kiwix::Manager manager = kiwix::Manager(&lib);
+
+    auto bookId = manager.addBookFromPathAndGetId("./test/example.zim");
+    EXPECT_NE(bookId, "");
+    kiwix::Book book = lib.getBookById(bookId);
+    EXPECT_EQ(book.getPath(), computeAbsolutePath("", "./test/example.zim"));
+    
+    const std::string pathToSave = "./pathToSave";
+    const std::string url = "url";
+    bookId = manager.addBookFromPathAndGetId("./test/example.zim", pathToSave, url, true);
+    book = lib.getBookById(bookId);
+    auto savedPath = computeAbsolutePath(removeLastPathElement(manager.writableLibraryPath), pathToSave);
+    EXPECT_EQ(book.getPath(), savedPath);
+    EXPECT_EQ(book.getUrl(), url);
+}

test/meson.build

@@ -1,4 +1,6 @@
-
+configure_file(input : 'data/example.zim',
+               output : 'example.zim',
+               copy: true )
 
 tests = [
     'parseUrl',
@@ -8,9 +10,15 @@ tests = [
     'stringTools',
     'pathTools',
     'kiwixserve',
-    'book'
+    'book',
+    'manager',
 ]
 
+if build_machine.system() != 'windows'
+  tests += ['server']
+endif
+
+
 
 gtest_dep = dependency('gtest',
                        main:true,
@@ -18,8 +26,15 @@ gtest_dep = dependency('gtest',
                        required:false)
 
 if gtest_dep.found() and not meson.is_cross_build()
+    configure_file(input : 'data/wikipedia_en_ray_charles_mini_2020-03.zim',
+                   output : 'zimfile.zim',
+                   copy: true )
+
     foreach test_name : tests
+        # XXX: implicit_include_directories must be set to false, otherwise
+        # XXX: '#include <regex>' includes the regex unit test binary
         test_exe = executable(test_name, [test_name+'.cpp'],
+                              implicit_include_directories: false,
                               link_with : kiwixlib,
                               link_args: extra_link_args,
                               dependencies : all_deps + [gtest_dep],

test/server.cpp

@@ -0,0 +1,410 @@
+
+#include "./httplib.h"
+#include "gtest/gtest.h"
+
+#include "../include/manager.h"
+#include "../include/server.h"
+#include "../include/name_mapper.h"
+
+
+using TestContextImpl = std::vector<std::pair<std::string, std::string> >;
+struct TestContext : TestContextImpl {
+  TestContext(const std::initializer_list<value_type>& il)
+    : TestContextImpl(il)
+  {}
+};
+
+std::ostream& operator<<(std::ostream& out, const TestContext& ctx)
+{
+  out << "Test context:\n";
+  for ( const auto& kv : ctx )
+    out << "\t" << kv.first << ": " << kv.second << "\n";
+  out << std::endl;
+  return out;
+}
+
+bool is_valid_etag(const std::string& etag)
+{
+  return etag.size() >= 2 &&
+         etag.front() == '"' &&
+         etag.back() == '"';
+}
+
+template<class T1, class T2>
+T1 concat(T1 a, const T2& b)
+{
+  a.insert(a.end(), b.begin(), b.end());
+  return a;
+}
+
+typedef httplib::Headers Headers;
+
+Headers invariantHeaders(Headers headers)
+{
+  headers.erase("Date");
+  return headers;
+}
+
+
+class ZimFileServer
+{
+public: // types
+  typedef std::shared_ptr<httplib::Response>  Response;
+
+public: // functions
+  ZimFileServer(int serverPort, std::string zimpath);
+  ~ZimFileServer();
+
+  Response GET(const char* path, const Headers& headers = Headers())
+  {
+    return client->Get(path, headers);
+  }
+
+  Response HEAD(const char* path, const Headers& headers = Headers())
+  {
+    return client->Head(path, headers);
+  }
+
+private: // data
+  kiwix::Library library;
+  kiwix::Manager manager;
+  std::unique_ptr<kiwix::HumanReadableNameMapper> nameMapper;
+  std::unique_ptr<kiwix::Server> server;
+  std::unique_ptr<httplib::Client> client;
+};
+
+ZimFileServer::ZimFileServer(int serverPort, std::string zimpath)
+: manager(&this->library)
+{
+  if (!manager.addBookFromPath(zimpath, zimpath, "", false))
+    throw std::runtime_error("Unable to add the ZIM file '" + zimpath + "'");
+
+  const std::string address = "127.0.0.1";
+  nameMapper.reset(new kiwix::HumanReadableNameMapper(library, false));
+  server.reset(new kiwix::Server(&library, nameMapper.get()));
+  server->setAddress(address);
+  server->setPort(serverPort);
+  server->setNbThreads(2);
+  server->setVerbose(false);
+
+  if ( !server->start() )
+    throw std::runtime_error("ZimFileServer failed to start");
+
+  client.reset(new httplib::Client(address, serverPort));
+}
+
+ZimFileServer::~ZimFileServer()
+{
+  server->stop();
+}
+
+class ServerTest : public ::testing::Test
+{
+protected:
+  std::unique_ptr<ZimFileServer>   zfs1_;
+
+  const int PORT = 8001;
+  const std::string ZIMFILE = "./test/zimfile.zim";
+
+protected:
+  void SetUp() override {
+    zfs1_.reset(new ZimFileServer(PORT, ZIMFILE));
+  }
+
+  void TearDown() override {
+    zfs1_.reset();
+  }
+};
+
+const bool WITH_ETAG = true;
+const bool NO_ETAG = false;
+
+struct Resource
+{
+  bool etag_expected;
+  const char* url;
+};
+
+std::ostream& operator<<(std::ostream& out, const Resource& r)
+{
+  out << "url: " << r.url;
+  return out;
+}
+
+typedef std::vector<Resource> ResourceCollection;
+
+const ResourceCollection resources200Compressible{
+  { WITH_ETAG, "/" },
+
+  { WITH_ETAG, "/skin/jquery-ui/jquery-ui.structure.min.css" },
+  { WITH_ETAG, "/skin/jquery-ui/jquery-ui.min.js" },
+  { WITH_ETAG, "/skin/jquery-ui/external/jquery/jquery.js" },
+  { WITH_ETAG, "/skin/jquery-ui/jquery-ui.theme.min.css" },
+  { WITH_ETAG, "/skin/jquery-ui/jquery-ui.min.css" },
+  { WITH_ETAG, "/skin/taskbar.js" },
+  { WITH_ETAG, "/skin/taskbar.css" },
+  { WITH_ETAG, "/skin/block_external.js" },
+
+  { NO_ETAG,   "/catalog/root.xml" },
+  { NO_ETAG,   "/catalog/searchdescription.xml" },
+  { NO_ETAG,   "/catalog/search" },
+
+  { NO_ETAG,   "/search?content=zimfile&pattern=abcd" },
+
+  { NO_ETAG,   "/suggest?content=zimfile&term=ray" },
+
+  { NO_ETAG,   "/catch/external?source=www.example.com" },
+
+  { WITH_ETAG, "/zimfile/A/index" },
+  { WITH_ETAG, "/zimfile/A/Ray_Charles" },
+};
+
+const ResourceCollection resources200Uncompressible{
+  { WITH_ETAG, "/skin/jquery-ui/images/animated-overlay.gif" },
+  { WITH_ETAG, "/skin/caret.png" },
+
+  { WITH_ETAG, "/meta?content=zimfile&name=title" },
+  { WITH_ETAG, "/meta?content=zimfile&name=description" },
+  { WITH_ETAG, "/meta?content=zimfile&name=language" },
+  { WITH_ETAG, "/meta?content=zimfile&name=name" },
+  { WITH_ETAG, "/meta?content=zimfile&name=tags" },
+  { WITH_ETAG, "/meta?content=zimfile&name=date" },
+  { WITH_ETAG, "/meta?content=zimfile&name=creator" },
+  { WITH_ETAG, "/meta?content=zimfile&name=publisher" },
+  { WITH_ETAG, "/meta?content=zimfile&name=favicon" },
+
+  { WITH_ETAG, "/zimfile/I/m/Ray_Charles_classic_piano_pose.jpg" },
+};
+
+ResourceCollection all200Resources()
+{
+  return concat(resources200Compressible, resources200Uncompressible);
+}
+
+TEST_F(ServerTest, 200)
+{
+  for ( const Resource& res : all200Resources() )
+    EXPECT_EQ(200, zfs1_->GET(res.url)->status) << "res.url: " << res.url;
+}
+
+TEST_F(ServerTest, CompressibleContentIsCompressedIfAcceptable)
+{
+  for ( const Resource& res : resources200Compressible ) {
+    const auto x = zfs1_->GET(res.url, { {"Accept-Encoding", "deflate"} });
+    EXPECT_EQ(200, x->status) << res;
+    EXPECT_EQ("deflate", x->get_header_value("Content-Encoding")) << res;
+    EXPECT_EQ("Accept-Encoding", x->get_header_value("Vary")) << res;
+  }
+}
+
+TEST_F(ServerTest, UncompressibleContentIsNotCompressed)
+{
+  for ( const Resource& res : resources200Uncompressible ) {
+    const auto x = zfs1_->GET(res.url, { {"Accept-Encoding", "deflate"} });
+    EXPECT_EQ(200, x->status) << res;
+    EXPECT_EQ("", x->get_header_value("Content-Encoding")) << res;
+  }
+}
+
+const char* urls404[] = {
+  "/non-existent-item",
+  "/skin/non-existent-skin-resource",
+  "/catalog",
+  "/catalog/non-existent-item",
+  "/meta",
+  "/meta?content=zimfile",
+  "/meta?content=zimfile&name=non-existent-item",
+  "/meta?content=non-existent-book&name=title",
+  "/random",
+  "/random?content=non-existent-book",
+  "/search",
+  "/suggest",
+  "/suggest?content=zimfile",
+  "/suggest?content=non-existent-book&term=abcd",
+  "/catch/external",
+  "/zimfile/A/non-existent-article",
+};
+
+TEST_F(ServerTest, 404)
+{
+  for ( const char* url : urls404 )
+    EXPECT_EQ(404, zfs1_->GET(url)->status) << "url: " << url;
+}
+
+TEST_F(ServerTest, SuccessfulSearchForAnArticleTitleRedirectsToTheArticle)
+{
+  auto g = zfs1_->GET("/search?content=zimfile&pattern=ray%20charles" );
+  ASSERT_EQ(302, g->status);
+  ASSERT_TRUE(g->has_header("Location"));
+  ASSERT_EQ("/zimfile/A/Ray_Charles", g->get_header_value("Location"));
+}
+
+TEST_F(ServerTest, RandomPageRedirectsToAnExistingArticle)
+{
+  auto g = zfs1_->GET("/random?content=zimfile");
+  ASSERT_EQ(302, g->status);
+  ASSERT_TRUE(g->has_header("Location"));
+  ASSERT_TRUE(g->get_header_value("Location").find("/zimfile/A/") != std::string::npos);
+}
+
+TEST_F(ServerTest, BookMainPageIsRedirectedToArticleIndex)
+{
+  auto g = zfs1_->GET("/zimfile");
+  ASSERT_EQ(302, g->status);
+  ASSERT_TRUE(g->has_header("Location"));
+  ASSERT_EQ("/zimfile/A/index", g->get_header_value("Location"));
+}
+
+TEST_F(ServerTest, HeadMethodIsSupported)
+{
+  for ( const Resource& res : all200Resources() )
+    EXPECT_EQ(200, zfs1_->HEAD(res.url)->status) << res;
+}
+
+TEST_F(ServerTest, TheResponseToHeadRequestHasNoBody)
+{
+  for ( const Resource& res : all200Resources() )
+    EXPECT_TRUE(zfs1_->HEAD(res.url)->body.empty()) << res;
+}
+
+TEST_F(ServerTest, HeadersAreTheSameInResponsesToHeadAndGetRequests)
+{
+  for ( const Resource& res : all200Resources() ) {
+    httplib::Headers g = zfs1_->GET(res.url)->headers;
+    httplib::Headers h = zfs1_->HEAD(res.url)->headers;
+    EXPECT_EQ(invariantHeaders(g), invariantHeaders(h)) << res;
+  }
+}
+
+TEST_F(ServerTest, ETagHeaderIsSetAsNeeded)
+{
+  for ( const Resource& res : all200Resources() ) {
+    const auto responseToGet = zfs1_->GET(res.url);
+    EXPECT_EQ(res.etag_expected, responseToGet->has_header("ETag")) << res;
+    if ( res.etag_expected ) {
+      EXPECT_TRUE(is_valid_etag(responseToGet->get_header_value("ETag")));
+    }
+  }
+}
+
+TEST_F(ServerTest, ETagIsTheSameInResponsesToDifferentRequestsOfTheSameURL)
+{
+  for ( const Resource& res : all200Resources() ) {
+    const auto h1 = zfs1_->HEAD(res.url);
+    const auto h2 = zfs1_->HEAD(res.url);
+    EXPECT_EQ(h1->get_header_value("ETag"), h2->get_header_value("ETag"));
+  }
+}
+
+TEST_F(ServerTest, ETagIsTheSameAcrossHeadAndGet)
+{
+  for ( const Resource& res : all200Resources() ) {
+    const auto g = zfs1_->GET(res.url);
+    const auto h = zfs1_->HEAD(res.url);
+    EXPECT_EQ(h->get_header_value("ETag"), g->get_header_value("ETag"));
+  }
+}
+
+TEST_F(ServerTest, DifferentServerInstancesProduceDifferentETags)
+{
+  ZimFileServer zfs2(PORT + 1, ZIMFILE);
+  for ( const Resource& res : all200Resources() ) {
+    if ( !res.etag_expected ) continue;
+    const auto h1 = zfs1_->HEAD(res.url);
+    const auto h2 = zfs2.HEAD(res.url);
+    EXPECT_NE(h1->get_header_value("ETag"), h2->get_header_value("ETag"));
+  }
+}
+
+TEST_F(ServerTest, CompressionInfluencesETag)
+{
+  for ( const Resource& res : resources200Compressible ) {
+    if ( ! res.etag_expected ) continue;
+    const auto g1 = zfs1_->GET(res.url);
+    const auto g2 = zfs1_->GET(res.url, { {"Accept-Encoding", ""} } );
+    const auto g3 = zfs1_->GET(res.url, { {"Accept-Encoding", "deflate"} } );
+    const auto etag = g1->get_header_value("ETag");
+    EXPECT_EQ(etag, g2->get_header_value("ETag"));
+    EXPECT_NE(etag, g3->get_header_value("ETag"));
+  }
+}
+
+TEST_F(ServerTest, ETagOfUncompressibleContentIsNotAffectedByAcceptEncoding)
+{
+  for ( const Resource& res : resources200Uncompressible ) {
+    if ( ! res.etag_expected ) continue;
+    const auto g1 = zfs1_->GET(res.url);
+    const auto g2 = zfs1_->GET(res.url, { {"Accept-Encoding", ""} } );
+    const auto g3 = zfs1_->GET(res.url, { {"Accept-Encoding", "deflate"} } );
+    const auto etag = g1->get_header_value("ETag");
+    EXPECT_EQ(etag, g2->get_header_value("ETag")) << res;
+    EXPECT_EQ(etag, g3->get_header_value("ETag")) << res;
+  }
+}
+
+// Pick from the response those headers that are required to be present in the
+// 304 (Not Modified) response if they would be set in the 200 (OK) response.
+// NOTE: The "Date" header (which should belong to that list as required
+// NOTE: by RFC 7232) is not included (since the result of this function
+// NOTE: will be used to check the equality of headers from the 200 and 304
+// NOTe: responses).
+Headers special304Headers(const httplib::Response& r)
+{
+  Headers result;
+  std::copy_if(
+    r.headers.begin(), r.headers.end(),
+    std::inserter(result, result.end()),
+    [](const Headers::value_type& x) {
+       return x.first == "Cache-Control"
+           || x.first == "Content-Location"
+           || x.first == "ETag"
+           || x.first == "Expires"
+           || x.first == "Vary";
+  });
+  return result;
+}
+
+// make a list of three etags with the given one in the middle
+std::string make_etag_list(const std::string& etag)
+{
+  return "\"x" + etag.substr(1) + ", "
+       + etag + ", "
+       + etag.substr(0, etag.size()-2) + "\"";
+}
+
+TEST_F(ServerTest, IfNoneMatchRequestsWithMatchingETagResultIn304Responses)
+{
+  const char* const encodings[] = { "", "deflate" };
+  for ( const Resource& res : all200Resources() ) {
+    for ( const char* enc: encodings ) {
+      if ( ! res.etag_expected ) continue;
+      const TestContext ctx{ {"url", res.url}, {"encoding", enc} };
+
+      const auto g = zfs1_->GET(res.url, { {"Accept-Encoding", enc} });
+      const auto etag = g->get_header_value("ETag");
+
+      const std::string etags = make_etag_list(etag);
+      const Headers headers{{"If-None-Match", etags}, {"Accept-Encoding", enc}};
+      const auto g2 = zfs1_->GET(res.url, headers );
+      const auto h = zfs1_->HEAD(res.url, headers );
+      EXPECT_EQ(304, h->status) << ctx;
+      EXPECT_EQ(304, g2->status) << ctx;
+      EXPECT_EQ(special304Headers(*g), special304Headers(*g2)) << ctx;
+      EXPECT_EQ(special304Headers(*g2), special304Headers(*h)) << ctx;
+      EXPECT_TRUE(g2->body.empty()) << ctx;
+    }
+  }
+}
+
+TEST_F(ServerTest, IfNoneMatchRequestsWithMismatchingETagResultIn200Responses)
+{
+  for ( const Resource& res : all200Resources() ) {
+    const auto g = zfs1_->GET(res.url);
+    const auto etag = g->get_header_value("ETag");
+    const auto etag2 = etag.substr(0, etag.size() - 1) + "x\"";
+    const auto h = zfs1_->HEAD(res.url, { {"If-None-Match", etag2} } );
+    const auto g2 = zfs1_->GET(res.url, { {"If-None-Match", etag2} } );
+    EXPECT_EQ(200, h->status);
+    EXPECT_EQ(200, g2->status);
+  }
+}