handle rate limiting by NewMotion API

app/src/main/java/net/vonforst/evmap/api/RateLimitInterceptor.kt

@@ -0,0 +1,33 @@
+package net.vonforst.evmap.api
+
+import com.google.common.util.concurrent.RateLimiter
+import okhttp3.Interceptor
+import okhttp3.Response
+
+
+class RateLimitInterceptor : Interceptor {
+    private val rateLimiter = RateLimiter.create(3.0)
+
+    override fun intercept(chain: Interceptor.Chain): Response {
+        val request = chain.request()
+        if (request.url.host == "my.newmotion.com") {
+            // limit requests sent to NewMotion to 3 per second
+            rateLimiter.acquire(1)
+
+            var response: Response = chain.proceed(request)
+            // 403 is how the NewMotion API indicates a rate limit error
+            if (!response.isSuccessful && response.code == 403) {
+                response.close()
+                // wait & retry
+                try {
+                    Thread.sleep(1000)
+                } catch (e: InterruptedException) {
+                }
+                response = chain.proceed(request)
+            }
+            return response
+        } else {
+            return chain.proceed(request)
+        }
+    }
+}

app/src/main/java/net/vonforst/evmap/api/availability/AvailabilityDetector.kt

@@ -3,6 +3,7 @@ package net.vonforst.evmap.api.availability
 import com.facebook.stetho.okhttp3.StethoInterceptor
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
+import net.vonforst.evmap.api.RateLimitInterceptor
 import net.vonforst.evmap.api.await
 import net.vonforst.evmap.api.goingelectric.ChargeLocation
 import net.vonforst.evmap.api.goingelectric.Chargepoint
@@ -123,6 +124,7 @@ private val cookieManager = CookieManager().apply {
 }
 
 private val okhttp = OkHttpClient.Builder()
+    .addInterceptor(RateLimitInterceptor())
     .addNetworkInterceptor(StethoInterceptor())
     .readTimeout(10, TimeUnit.SECONDS)
     .connectTimeout(10, TimeUnit.SECONDS)