#20: headers injector

Author: lucas34

README.md

@@ -9,6 +9,7 @@
   - [Disk cache limit](#disk-cache-limit)
   - [Listen caching progress](#listen-caching-progress)
   - [Providing names for cached files](#providing-names-for-cached-files)
+  - [Adding custom http headers](#adding-custom-http-headers)
   - [Using exoPlayer](#using-exoplayer)
   - [Sample](#sample)
 - [Known problems](#known-problems)
@@ -137,6 +138,25 @@ HttpProxyCacheServer proxy = HttpProxyCacheServer.Builder(context)
     .build()
 ```
 
+### Adding custom http headers
+You can add custom headers to requests with help of `HeadersInjector`:
+``` java
+public class UserAgentHeadersInjector implements HeaderInjector {
+
+    @Override
+    public Map<String, String> addHeaders(String url) {
+        return Maps.newHashMap("User-Agent", "Cool app v1.1");
+    }
+}
+
+private HttpProxyCacheServer newProxy() {
+    return new HttpProxyCacheServer.Builder(this)
+            .headerInjector(new UserAgentHeadersInjector())
+            .build();
+}
+
+```
+
 ### Using exoPlayer
 You can use [`exoPlayer`](https://google.github.io/ExoPlayer/) with `AndroidVideoCache`. See `sample` app in [`exoPlayer`](https://github.com/danikula/AndroidVideoCache/tree/exoPlayer) branch. Note [exoPlayer supports](https://github.com/google/ExoPlayer/commit/bd7be1b5e7cc41a59ebbc348d394820fc857db92) cache as well.  
 

library/src/main/java/com/danikula/videocache/Config.java

@@ -2,6 +2,7 @@
 
 import com.danikula.videocache.file.DiskUsage;
 import com.danikula.videocache.file.FileNameGenerator;
+import com.danikula.videocache.headers.HeaderInjector;
 import com.danikula.videocache.sourcestorage.SourceInfoStorage;
 
 import java.io.File;
@@ -17,12 +18,14 @@ class Config {
     public final FileNameGenerator fileNameGenerator;
     public final DiskUsage diskUsage;
     public final SourceInfoStorage sourceInfoStorage;
+    public final HeaderInjector headerInjector;
 
-    Config(File cacheRoot, FileNameGenerator fileNameGenerator, DiskUsage diskUsage, SourceInfoStorage sourceInfoStorage) {
+    Config(File cacheRoot, FileNameGenerator fileNameGenerator, DiskUsage diskUsage, SourceInfoStorage sourceInfoStorage, HeaderInjector headerInjector) {
         this.cacheRoot = cacheRoot;
         this.fileNameGenerator = fileNameGenerator;
         this.diskUsage = diskUsage;
         this.sourceInfoStorage = sourceInfoStorage;
+        this.headerInjector = headerInjector;
     }
 
     File generateCacheFile(String url) {

library/src/main/java/com/danikula/videocache/HttpProxyCacheServer.java

@@ -8,6 +8,8 @@
 import com.danikula.videocache.file.Md5FileNameGenerator;
 import com.danikula.videocache.file.TotalCountLruDiskUsage;
 import com.danikula.videocache.file.TotalSizeLruDiskUsage;
+import com.danikula.videocache.headers.EmptyHeadersInjector;
+import com.danikula.videocache.headers.HeaderInjector;
 import com.danikula.videocache.sourcestorage.SourceInfoStorage;
 import com.danikula.videocache.sourcestorage.SourceInfoStorageFactory;
 
@@ -350,12 +352,14 @@ public static final class Builder {
         private FileNameGenerator fileNameGenerator;
         private DiskUsage diskUsage;
         private SourceInfoStorage sourceInfoStorage;
+        private HeaderInjector headerInjector;
 
         public Builder(Context context) {
             this.sourceInfoStorage = SourceInfoStorageFactory.newSourceInfoStorage(context);
             this.cacheRoot = StorageUtils.getIndividualCacheDirectory(context);
             this.diskUsage = new TotalSizeLruDiskUsage(DEFAULT_MAX_SIZE);
             this.fileNameGenerator = new Md5FileNameGenerator();
+            this.headerInjector = new EmptyHeadersInjector();
         }
 
         /**
@@ -426,6 +430,17 @@ public Builder diskUsage(DiskUsage diskUsage) {
             return this;
         }
 
+        /**
+         * Add headers along the request to the server
+         *
+         * @param headerInjector to inject header base on url
+         * @return a builder
+         */
+        public Builder headerInjector(HeaderInjector headerInjector) {
+            this.headerInjector = checkNotNull(headerInjector);
+            return this;
+        }
+
         /**
          * Builds new instance of {@link HttpProxyCacheServer}.
          *
@@ -437,7 +452,7 @@ public HttpProxyCacheServer build() {
         }
 
         private Config buildConfig() {
-            return new Config(cacheRoot, fileNameGenerator, diskUsage, sourceInfoStorage);
+            return new Config(cacheRoot, fileNameGenerator, diskUsage, sourceInfoStorage, headerInjector);
         }
 
     }

library/src/main/java/com/danikula/videocache/HttpProxyCacheServerClients.java

@@ -79,7 +79,7 @@ public int getClientsCount() {
     }
 
     private HttpProxyCache newHttpProxyCache() throws ProxyCacheException {
-        HttpUrlSource source = new HttpUrlSource(url, config.sourceInfoStorage);
+        HttpUrlSource source = new HttpUrlSource(url, config.sourceInfoStorage, config.headerInjector);
         FileCache cache = new FileCache(config.generateCacheFile(url), config.diskUsage);
         HttpProxyCache httpProxyCache = new HttpProxyCache(source, cache);
         httpProxyCache.registerCacheListener(uiCacheListener);

library/src/main/java/com/danikula/videocache/HttpUrlSource.java

@@ -2,6 +2,8 @@
 
 import android.text.TextUtils;
 
+import com.danikula.videocache.headers.EmptyHeadersInjector;
+import com.danikula.videocache.headers.HeaderInjector;
 import com.danikula.videocache.sourcestorage.SourceInfoStorage;
 import com.danikula.videocache.sourcestorage.SourceInfoStorageFactory;
 
@@ -14,6 +16,7 @@
 import java.io.InterruptedIOException;
 import java.net.HttpURLConnection;
 import java.net.URL;
+import java.util.Map;
 
 import static com.danikula.videocache.Preconditions.checkNotNull;
 import static com.danikula.videocache.ProxyCacheUtils.DEFAULT_BUFFER_SIZE;
@@ -34,6 +37,7 @@ public class HttpUrlSource implements Source {
 
     private static final int MAX_REDIRECTS = 5;
     private final SourceInfoStorage sourceInfoStorage;
+    private final HeaderInjector headerInjector;
     private SourceInfo sourceInfo;
     private HttpURLConnection connection;
     private InputStream inputStream;
@@ -43,7 +47,12 @@ public HttpUrlSource(String url) {
     }
 
     public HttpUrlSource(String url, SourceInfoStorage sourceInfoStorage) {
+        this(url, sourceInfoStorage, new EmptyHeadersInjector());
+    }
+
+    public HttpUrlSource(String url, SourceInfoStorage sourceInfoStorage, HeaderInjector headerInjector) {
         this.sourceInfoStorage = checkNotNull(sourceInfoStorage);
+        this.headerInjector = checkNotNull(headerInjector);
         SourceInfo sourceInfo = sourceInfoStorage.get(url);
         this.sourceInfo = sourceInfo != null ? sourceInfo :
                 new SourceInfo(url, Integer.MIN_VALUE, ProxyCacheUtils.getSupposablyMime(url));
@@ -52,6 +61,7 @@ public HttpUrlSource(String url, SourceInfoStorage sourceInfoStorage) {
     public HttpUrlSource(HttpUrlSource source) {
         this.sourceInfo = source.sourceInfo;
         this.sourceInfoStorage = source.sourceInfoStorage;
+        this.headerInjector = source.headerInjector;
     }
 
     @Override
@@ -150,6 +160,7 @@ private HttpURLConnection openConnection(long offset, int timeout) throws IOExce
         do {
             LOG.debug("Open connection " + (offset > 0 ? " with offset " + offset : "") + " to " + url);
             connection = (HttpURLConnection) new URL(url).openConnection();
+            injectCustomHeaders(connection, url);
             if (offset > 0) {
                 connection.setRequestProperty("Range", "bytes=" + offset + "-");
             }
@@ -171,6 +182,13 @@ private HttpURLConnection openConnection(long offset, int timeout) throws IOExce
         return connection;
     }
 
+    private void injectCustomHeaders(HttpURLConnection connection, String url) {
+        Map<String, String> extraHeaders = headerInjector.addHeaders(url);
+        for (Map.Entry<String, String> header : extraHeaders.entrySet()) {
+            connection.setRequestProperty(header.getKey(), header.getValue());
+        }
+    }
+
     public synchronized String getMime() throws ProxyCacheException {
         if (TextUtils.isEmpty(sourceInfo.mime)) {
             fetchContentInfo();

library/src/main/java/com/danikula/videocache/headers/EmptyHeadersInjector.java

@@ -0,0 +1,18 @@
+package com.danikula.videocache.headers;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Empty {@link HeaderInjector} implementation.
+ *
+ * @author Lucas Nelaupe (https://github.com/lucas34).
+ */
+public class EmptyHeadersInjector implements HeaderInjector {
+
+    @Override
+    public Map<String, String> addHeaders(String url) {
+        return new HashMap<>();
+    }
+
+}

library/src/main/java/com/danikula/videocache/headers/HeaderInjector.java

@@ -0,0 +1,20 @@
+package com.danikula.videocache.headers;
+
+import java.util.Map;
+
+/**
+ * Allows to add custom headers to server's requests.
+ *
+ * @author Lucas Nelaupe (https://github.com/lucas34).
+ */
+public interface HeaderInjector {
+
+    /**
+     * Adds headers to server's requests for corresponding url.
+     *
+     * @param url an url headers will be added for
+     * @return a map with headers, where keys are header's names, and values are header's values. {@code null} is not acceptable!
+     */
+    Map<String, String> addHeaders(String url);
+
+}

test/src/test/java/com/danikula/videocache/HttpProxyCacheServerTest.java

@@ -6,11 +6,13 @@
 import com.danikula.android.garden.io.IoUtils;
 import com.danikula.videocache.file.FileNameGenerator;
 import com.danikula.videocache.file.Md5FileNameGenerator;
+import com.danikula.videocache.headers.HeaderInjector;
 import com.danikula.videocache.support.ProxyCacheTestUtils;
 import com.danikula.videocache.support.Response;
 
 import org.junit.Before;
 import org.junit.Test;
+import org.mockito.Mockito;
 import org.robolectric.RuntimeEnvironment;
 
 import java.io.File;
@@ -36,6 +38,8 @@
 import static com.danikula.videocache.support.ProxyCacheTestUtils.readProxyResponse;
 import static com.danikula.videocache.support.ProxyCacheTestUtils.resetSystemProxy;
 import static org.fest.assertions.api.Assertions.assertThat;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
 
 /**
  * @author Alexey Danilov (danikula@gmail.com).
@@ -360,6 +364,20 @@ public void testDoesNotWorkWithoutCustomProxySelector() throws Exception {
         assertThat(proxiedUrl).isEqualTo(HTTP_DATA_URL);
     }
 
+    @Test
+    public void testHeadersInjectorIsInvoked() throws Exception {
+        HeaderInjector mockedHeaderInjector = Mockito.mock(HeaderInjector.class);
+
+        HttpProxyCacheServer proxy = new HttpProxyCacheServer.Builder(RuntimeEnvironment.application)
+                .headerInjector(mockedHeaderInjector)
+                .build();
+
+        readProxyResponse(proxy, HTTP_DATA_URL);
+        proxy.shutdown();
+
+        verify(mockedHeaderInjector, times(2)).addHeaders(HTTP_DATA_URL);   // content info & fetch data requests
+    }
+
     private Pair<File, Response> readProxyData(String url, int offset) throws IOException {
         File file = file(cacheFolder, url);
         HttpProxyCacheServer proxy = newProxy(cacheFolder);

test/src/test/java/com/danikula/videocache/HttpUrlSourceTest.java

@@ -1,5 +1,6 @@
 package com.danikula.videocache;
 
+import com.danikula.videocache.headers.HeaderInjector;
 import com.danikula.videocache.sourcestorage.SourceInfoStorage;
 import com.danikula.videocache.sourcestorage.SourceInfoStorageFactory;
 import com.danikula.videocache.support.ProxyCacheTestUtils;
@@ -25,6 +26,7 @@
 import static org.fest.assertions.api.Assertions.assertThat;
 import static org.fest.assertions.api.Assertions.fail;
 import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.when;
 
 /**
  * @author Alexey Danilov (danikula@gmail.com).
@@ -156,6 +158,16 @@ public void testNotOpenableHttpUrlSourceOpen() throws Exception {
         fail("source.open() should throw exception");
     }
 
+    @Test(expected = NullPointerException.class)
+    public void testHeaderInjectorNullNotAcceptable() throws Exception {
+        HeaderInjector mockedHeaderInjector = Mockito.mock(HeaderInjector.class);
+        when(mockedHeaderInjector.addHeaders(Mockito.anyString())).thenReturn(null);
+        SourceInfoStorage emptySourceInfoStorage = SourceInfoStorageFactory.newEmptySourceInfoStorage();
+        HttpUrlSource source = new HttpUrlSource(HTTP_DATA_URL_ONE_REDIRECT, emptySourceInfoStorage, mockedHeaderInjector);
+        source.open(0);
+        fail("source.open should throw NPE!");
+    }
+
     private void readSource(Source source, byte[] target) throws ProxyCacheException {
         byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
         int totalRead = 0;