背景
- App合規(guī)現(xiàn)在是越來越嚴(yán)了，也越來越多App被通報，為了能隱私合規(guī)呢，我對公司App也進(jìn)行很多的整改。其中最主要的是通過ASM字節(jié)碼去攔截第三方庫頻繁調(diào)用隱私方法的問題。
- 主要思路就是找到第三方庫頻繁調(diào)用隱私方法的方法，將其替換成我們自己的方法。AsmActualCombat項目地址：https://github.com/Peakmain/AsmActualCombat
- 那今天呢，講的是對Glide進(jìn)行封裝，移除User-Agent，相當(dāng)來說簡單多了，主要要熟悉代碼
-
背景：我們公司App加載網(wǎng)絡(luò)圖片時候，App移動應(yīng)用檢測的時候說我們應(yīng)用自身獲取個人信息行為，描述說的是我們有圖片上傳行為，看了堆棧，主要問題是加載圖片的時候，user-Agent有讀取設(shè)備型號行為
image.png - 于是我就猜測是Glide在加載網(wǎng)絡(luò)的時候，它內(nèi)部設(shè)置了User-Agent，那就讓我們一起來驗證咋們的猜測吧。
源碼
Glide的簡單使用
Glide.with(imageView.getContext().getApplicationContext()).asDrawable().load(url).into(imageView);
因為我們主要想知道加載圖片的時候是否設(shè)置了User-Agent，那肯定就是主要看加載圖片時的into源碼
into源碼
public ViewTarget<ImageView, TranscodeType> into(@NonNull ImageView view) {
Util.assertMainThread();
Preconditions.checkNotNull(view);
RequestOptions requestOptions = this.requestOptions;
//代碼省略
return into(
glideContext.buildImageViewTarget(view, transcodeClass),
/*targetListener=*/ null,
requestOptions);
}
buildImageViewTarget
public <X> ViewTarget<ImageView, X> buildImageViewTarget(
@NonNull ImageView imageView, @NonNull Class<X> transcodeClass) {
return imageViewTargetFactory.buildTarget(imageView, transcodeClass);
}
public class ImageViewTargetFactory {
@NonNull
@SuppressWarnings("unchecked")
public <Z> ViewTarget<ImageView, Z> buildTarget(@NonNull ImageView view,
@NonNull Class<Z> clazz) {
if (Bitmap.class.equals(clazz)) {
return (ViewTarget<ImageView, Z>) new BitmapImageViewTarget(view);
} else if (Drawable.class.isAssignableFrom(clazz)) {
return (ViewTarget<ImageView, Z>) new DrawableImageViewTarget(view);
} else {
throw new IllegalArgumentException(
"Unhandled class: " + clazz + ", try .as*(Class).transcode(ResourceTranscoder)");
}
}
}
- 此時我們無論點擊BitmapImageViewTarget還是DrawableImageViewTarget他們的父類其實都是ImageViewTarget,而ImageViewTarget的父類是ViewTarget
- 所以上面我們的into源碼第一個參數(shù)實際是ViewTarget，第二個參數(shù)為null第三個參數(shù)暫時不用關(guān)心，如果需要我們呢再回來看。上面就可以變成這樣
public ViewTarget<ImageView, TranscodeType> into(@NonNull ImageView view) {
Util.assertMainThread();
Preconditions.checkNotNull(view);
RequestOptions requestOptions = this.requestOptions;
//代碼省略
return into(
ViewTarget
null,
requestOptions);
}
繼續(xù)往下走
private <Y extends Target<TranscodeType>> Y into(
@NonNull Y target,
@Nullable RequestListener<TranscodeType> targetListener,
@NonNull RequestOptions options) {
Util.assertMainThread();
Preconditions.checkNotNull(target);
if (!isModelSet) {
throw new IllegalArgumentException("You must call #load() before calling #into()");
}
options = options.autoClone();
Request request = buildRequest(target, targetListener, options);//????①
Request previous = target.getRequest();
//代碼省略
requestManager.clear(target);
target.setRequest(request);
requestManager.track(target, request);//????②
return target;
}
- 注釋①，它的作用主要是創(chuàng)建一個Request,點擊Request我們發(fā)現(xiàn)它是一個接口，那么我么就看看它的實現(xiàn)類是啥
private Request buildRequest(
Target<TranscodeType> target,
@Nullable RequestListener<TranscodeType> targetListener,
RequestOptions requestOptions) {
return buildRequestRecursive(
target,
targetListener,
/*parentCoordinator=*/ null,
transitionOptions,
requestOptions.getPriority(),
requestOptions.getOverrideWidth(),
requestOptions.getOverrideHeight(),
requestOptions);
}
private Request buildRequestRecursive(
Target<TranscodeType> target,
@Nullable RequestListener<TranscodeType> targetListener,
@Nullable RequestCoordinator parentCoordinator,
TransitionOptions<?, ? super TranscodeType> transitionOptions,
Priority priority,
int overrideWidth,
int overrideHeight,
RequestOptions requestOptions) {
// Build the ErrorRequestCoordinator first if necessary so we can update parentCoordinator.
ErrorRequestCoordinator errorRequestCoordinator = null;
Request mainRequest =
buildThumbnailRequestRecursive(
target,
targetListener,
parentCoordinator,
transitionOptions,
priority,
overrideWidth,
overrideHeight,
requestOptions);
if (errorRequestCoordinator == null) {
return mainRequest;
}
//代碼省略
return errorRequestCoordinator;
}
private Request buildThumbnailRequestRecursive(
Target<TranscodeType> target,
RequestListener<TranscodeType> targetListener,
@Nullable RequestCoordinator parentCoordinator,
TransitionOptions<?, ? super TranscodeType> transitionOptions,
Priority priority,
int overrideWidth,
int overrideHeight,
RequestOptions requestOptions) {
//代碼省略
if (thumbnailBuilder != null) {
} else if (thumbSizeMultiplier != null) {
return obtainRequest(
target,
targetListener,
requestOptions,
parentCoordinator,
transitionOptions,
priority,
overrideWidth,
overrideHeight);
}
}
這里我偷懶就直接去掉不必要的判斷代碼了,因為我們代碼都沒有去配置那些參數(shù)，所以一般前面兩個判斷是不會進(jìn)來的。
private Request obtainRequest(
Target<TranscodeType> target,
RequestListener<TranscodeType> targetListener,
RequestOptions requestOptions,
RequestCoordinator requestCoordinator,
TransitionOptions<?, ? super TranscodeType> transitionOptions,
Priority priority,
int overrideWidth,
int overrideHeight) {
return SingleRequest.obtain(
context,
glideContext,
model,
transcodeClass,
requestOptions,
overrideWidth,
overrideHeight,
priority,
target,
targetListener,
requestListener,
requestCoordinator,
glideContext.getEngine(),
transitionOptions.getTransitionFactory());
}
這時候我們可以看到了，實現(xiàn)類是SingleRequest，利用享元模式創(chuàng)建的實例
- 注釋②，上面注釋①我們知道了request是SingleRequest，繼續(xù)跟下源碼
void track(Target<?> target, Request request) {
targetTracker.track(target);
requestTracker.runRequest(request);
}
public void runRequest(Request request) {
requests.add(request);
if (!isPaused) {
request.begin();
} else {
pendingRequests.add(request);
}
}
之后走到的是request的begin，也就是SingleRequest的begin方法
SingleRequest的begin源碼
public void begin() {
if (status == Status.RUNNING) {//????①
throw new IllegalArgumentException("Cannot restart a running request");
}
if (status == Status.COMPLETE) {
onResourceReady(resource, DataSource.MEMORY_CACHE);
return;
}
status = Status.WAITING_FOR_SIZE;
if (Util.isValidDimensions(overrideWidth, overrideHeight)) {
onSizeReady(overrideWidth, overrideHeight);//????②
} else {
target.getSize(this);
}
}
- 注釋①，state的默認(rèn)初始是在init方法,而init是SingleRequest.obtain調(diào)用初始化的
private void init(...) {
status = Status.PENDING;
}
所以注釋①的判斷為false，會往下走，一直走到注釋②(圖片的寬高都正常的情況下)
- 注釋②,onSizeReady源碼
public void onSizeReady(int width, int height) {
stateVerifier.throwIfRecycled();
if (status != Status.WAITING_FOR_SIZE) {
return;
}
status = Status.RUNNING;
float sizeMultiplier = requestOptions.getSizeMultiplier();
this.width = maybeApplySizeMultiplier(width, sizeMultiplier);
this.height = maybeApplySizeMultiplier(height, sizeMultiplier);
loadStatus = engine.load(
glideContext,
model,
requestOptions.getSignature(),
this.width,
this.height,
requestOptions.getResourceClass(),
transcodeClass,
priority,
requestOptions.getDiskCacheStrategy(),
requestOptions.getTransformations(),
requestOptions.isTransformationRequired(),
requestOptions.isScaleOnlyOrNoTransform(),
requestOptions.getOptions(),
requestOptions.isMemoryCacheable(),
requestOptions.getUseUnlimitedSourceGeneratorsPool(),
requestOptions.getUseAnimationPool(),
requestOptions.getOnlyRetrieveFromCache(),
this);
if (status != Status.RUNNING) {
loadStatus = null;
}
}
public <R> LoadStatus load(
GlideContext glideContext,
Object model,
Key signature,
int width,
int height,
Class<?> resourceClass,
Class<R> transcodeClass,
Priority priority,
DiskCacheStrategy diskCacheStrategy,
Map<Class<?>, Transformation<?>> transformations,
boolean isTransformationRequired,
boolean isScaleOnlyOrNoTransform,
Options options,
boolean isMemoryCacheable,
boolean useUnlimitedSourceExecutorPool,
boolean useAnimationPool,
boolean onlyRetrieveFromCache,
ResourceCallback cb) {
Util.assertMainThread();
long startTime = LogTime.getLogTime();
//緩存邏輯省略
EngineJob<R> engineJob =
engineJobFactory.build(
key,
isMemoryCacheable,
useUnlimitedSourceExecutorPool,
useAnimationPool,
onlyRetrieveFromCache);
DecodeJob<R> decodeJob =
decodeJobFactory.build(
glideContext,
model,
key,
signature,
width,
height,
resourceClass,
transcodeClass,
priority,
diskCacheStrategy,
transformations,
isTransformationRequired,
isScaleOnlyOrNoTransform,
onlyRetrieveFromCache,
options,
engineJob);
jobs.put(key, engineJob);
engineJob.addCallback(cb);
engineJob.start(decodeJob);
return new LoadStatus(cb, engineJob);
}
緩存邏輯我們就直接跳過，因為我們主要關(guān)注的是網(wǎng)絡(luò)加載圖片
engineJob的start
public void start(DecodeJob<R> decodeJob) {
this.decodeJob = decodeJob;
GlideExecutor executor = decodeJob.willDecodeFromCache()
? diskCacheExecutor
: getActiveSourceExecutor();
executor.execute(decodeJob);
}
執(zhí)行的實際是decodeJob的run方法
public void run() {
TraceCompat.beginSection("DecodeJob#run");
DataFetcher<?> localFetcher = currentFetcher;
try {
if (isCancelled) {
notifyFailed();
return;
}
runWrapped();
} catch (Throwable t) {
} finally {
if (localFetcher != null) {
localFetcher.cleanup();
}
TraceCompat.endSection();
}
}
private void runWrapped() {
switch (runReason) {
case INITIALIZE://????①
stage = getNextStage(Stage.INITIALIZE);//????②
currentGenerator = getNextGenerator();//????③
runGenerators();//????④
break;
case SWITCH_TO_SOURCE_SERVICE:
runGenerators();
break;
case DECODE_DATA:
decodeFromRetrievedData();
break;
default:
throw new IllegalStateException("Unrecognized run reason: " + runReason);
}
}
- 注釋①，runReason在init的時候賦值為INITIALIZE
- 注釋②，我們需要這里我們Stage是INITIALIZE
private Stage getNextStage(Stage current) {
switch (current) {
case INITIALIZE:
return diskCacheStrategy.decodeCachedResource()
? Stage.RESOURCE_CACHE : getNextStage(Stage.RESOURCE_CACHE);
case RESOURCE_CACHE:
return diskCacheStrategy.decodeCachedData()
? Stage.DATA_CACHE : getNextStage(Stage.DATA_CACHE);
//代碼省略
}
}
我們并沒有對磁盤緩存進(jìn)行修改，那么diskCacheStrategy肯定是默認(rèn)配置，我們一步步往回走，走到初始化它的代碼位置，發(fā)現(xiàn)最終實際是在onSizeReady的時候初始化的
public void onSizeReady(int width, int height) {
loadStatus = engine.load(
glideContext,
model,
requestOptions.getSignature(),
this.width,
this.height,
requestOptions.getResourceClass(),
transcodeClass,
priority,
requestOptions.getDiskCacheStrategy(),//這里初始化的
requestOptions.getTransformations(),
requestOptions.isTransformationRequired(),
requestOptions.isScaleOnlyOrNoTransform(),
requestOptions.getOptions(),
requestOptions.isMemoryCacheable(),
requestOptions.getUseUnlimitedSourceGeneratorsPool(),
requestOptions.getUseAnimationPool(),
requestOptions.getOnlyRetrieveFromCache(),
this);
}
public class RequestOptions implements Cloneable {
private DiskCacheStrategy diskCacheStrategy = DiskCacheStrategy.AUTOMATIC;
public final DiskCacheStrategy getDiskCacheStrategy() {
return diskCacheStrategy;
}
}
public static final DiskCacheStrategy AUTOMATIC = new DiskCacheStrategy() {
@Override
public boolean isDataCacheable(DataSource dataSource) {
return dataSource == DataSource.REMOTE;
}
@Override
public boolean isResourceCacheable(boolean isFromAlternateCacheKey, DataSource dataSource,
EncodeStrategy encodeStrategy) {
return ((isFromAlternateCacheKey && dataSource == DataSource.DATA_DISK_CACHE)
|| dataSource == DataSource.LOCAL)
&& encodeStrategy == EncodeStrategy.TRANSFORMED;
}
@Override
public boolean decodeCachedResource() {
return true;//返回true
}
@Override
public boolean decodeCachedData() {
return true;
}
};
我們回到getNextStage，我們發(fā)現(xiàn)diskCacheStrategy.decodeCachedResource()返回的是true,也就是說注釋② getNextStage返回Stage.RESOURCE_CACHE
- 注釋③,getNextGenerator
private DataFetcherGenerator getNextGenerator() {
switch (stage) {
case RESOURCE_CACHE:
return new ResourceCacheGenerator(decodeHelper, this);
//代碼省略
default:
throw new IllegalStateException("Unrecognized stage: " + stage);
}
}
注釋③實際是創(chuàng)建ResourceCacheGenerator實例并復(fù)制給了currentGenerator
- 注釋④，我們主要分析runGenerators
runGenerators
private void runGenerators() {
currentThread = Thread.currentThread();
startFetchTime = LogTime.getLogTime();
boolean isStarted = false;
while (!isCancelled && currentGenerator != null
&& !(isStarted = currentGenerator.startNext())) {//????①
}
}
- 上面我們知道currentGenerator是ResourceCacheGenerator，也就是說currentGenerator.startNext()調(diào)用的是ResourceCacheGenerator.startNext()
ResourceCacheGenerator 的StartNext
public boolean startNext() {
List<Key> sourceIds = helper.getCacheKeys();
if (sourceIds.isEmpty()) {
return false;
}
List<Class<?>> resourceClasses = helper.getRegisteredResourceClasses();
while (modelLoaders == null || !hasNextModelLoader()) {
resourceClassIndex++;
if (resourceClassIndex >= resourceClasses.size()) {
sourceIdIndex++;
if (sourceIdIndex >= sourceIds.size()) {
return false;
}
resourceClassIndex = 0;
}
Key sourceId = sourceIds.get(sourceIdIndex);
Class<?> resourceClass = resourceClasses.get(resourceClassIndex);
Transformation<?> transformation = helper.getTransformation(resourceClass);
currentKey =
new ResourceCacheKey(// NOPMD AvoidInstantiatingObjectsInLoops
helper.getArrayPool(),
sourceId,
helper.getSignature(),
helper.getWidth(),
helper.getHeight(),
transformation,
resourceClass,
helper.getOptions());
cacheFile = helper.getDiskCache().get(currentKey);
if (cacheFile != null) {
sourceKey = sourceId;
modelLoaders = helper.getModelLoaders(cacheFile);//????①
modelLoaderIndex = 0;
}
}
loadData = null;
boolean started = false;
while (!started && hasNextModelLoader()) {
ModelLoader<File, ?> modelLoader = modelLoaders.get(modelLoaderIndex++);
loadData = modelLoader.buildLoadData(cacheFile,
helper.getWidth(), helper.getHeight(), helper.getOptions());//????②
if (loadData != null && helper.hasLoadPath(loadData.fetcher.getDataClass())) {
started = true;
loadData.fetcher.loadData(helper.getPriority(), this);
}
}
return started;
}
- 注釋①，我們首先看下modelLoader是什么
List<ModelLoader<File, ?>> getModelLoaders(File file)
throws Registry.NoModelLoaderAvailableException {
return glideContext.getRegistry().getModelLoaders(file);
}
public <Model> List<ModelLoader<Model, ?>> getModelLoaders(@NonNull Model model) {
List<ModelLoader<Model, ?>> result = modelLoaderRegistry.getModelLoaders(model);
return result;
}
public synchronized <A> List<ModelLoader<A, ?>> getModelLoaders(@NonNull A model) {
List<ModelLoader<A, ?>> modelLoaders = getModelLoadersForClass(getClass(model));
int size = modelLoaders.size();
//代碼省略
return filteredLoaders;
}
private <A> List<ModelLoader<A, ?>> getModelLoadersForClass(@NonNull Class<A> modelClass) {
List<ModelLoader<A, ?>> loaders = cache.get(modelClass);
if (loaders == null) {
loaders = Collections.unmodifiableList(multiModelLoaderFactory.build(modelClass));
cache.put(modelClass, loaders);
}
return loaders;
}
synchronized <Model> List<ModelLoader<Model, ?>> build(@NonNull Class<Model> modelClass) {
try {
List<ModelLoader<Model, ?>> loaders = new ArrayList<>();
for (Entry<?, ?> entry : entries) {
if (alreadyUsedEntries.contains(entry)) {
continue;
}
if (entry.handles(modelClass)) {
alreadyUsedEntries.add(entry);
loaders.add(this.<Model, Object>build(entry));
alreadyUsedEntries.remove(entry);
}
}
return loaders;
} catch (Throwable t) {
alreadyUsedEntries.clear();
throw t;
}
}
private <Model, Data> ModelLoader<Model, Data> build(@NonNull Entry<?, ?> entry) {
return (ModelLoader<Model, Data>) Preconditions.checkNotNull(entry.factory.build(this));
}
ModelLoader<T, Y> build(@NonNull MultiModelLoaderFactory multiFactory);
走到這里我們發(fā)現(xiàn)我們走不下去了，因為ModelLoaderFactory是個接口，那我們想知道entry.factory是什么，就需要知道entry是啥，我們回到build方法，我們來看看entries是啥玩意
private final List<Entry<?, ?>> entries = new ArrayList<>();
我們發(fā)現(xiàn)就是一個List，既然是私有的，那就說明它一定是賦值或者有add方法
private <Model, Data> void add(
@NonNull Class<Model> modelClass,
@NonNull Class<Data> dataClass,
@NonNull ModelLoaderFactory<? extends Model, ? extends Data> factory,
boolean append) {
Entry<Model, Data> entry = new Entry<>(modelClass, dataClass, factory);
entries.add(append ? entries.size() : 0, entry);
}
synchronized <Model, Data> void append(
@NonNull Class<Model> modelClass,
@NonNull Class<Data> dataClass,
@NonNull ModelLoaderFactory<? extends Model, ? extends Data> factory) {
add(modelClass, dataClass, factory, /*append=*/ true);
}
public synchronized <Model, Data> void append(
@NonNull Class<Model> modelClass,
@NonNull Class<Data> dataClass,
@NonNull ModelLoaderFactory<? extends Model, ? extends Data> factory) {
multiModelLoaderFactory.append(modelClass, dataClass, factory);
cache.clear();
}
public <Model, Data> Registry append(
@NonNull Class<Model> modelClass, @NonNull Class<Data> dataClass,
@NonNull ModelLoaderFactory<Model, Data> factory) {
modelLoaderRegistry.append(modelClass, dataClass, factory);
return this;
}
我們再繼續(xù)反推我們發(fā)現(xiàn)會走到Glide的初始化
Glide(
@NonNull Context context,
@NonNull Engine engine,
@NonNull MemoryCache memoryCache,
@NonNull BitmapPool bitmapPool,
@NonNull ArrayPool arrayPool,
@NonNull RequestManagerRetriever requestManagerRetriever,
@NonNull ConnectivityMonitorFactory connectivityMonitorFactory,
int logLevel,
@NonNull RequestOptions defaultRequestOptions,
@NonNull Map<Class<?>, TransitionOptions<?, ?>> defaultTransitionOptions) {
registry
.append(ByteBuffer.class, new ByteBufferEncoder())
.append(InputStream.class, new StreamEncoder(arrayPool))
/* Bitmaps */
.append(Registry.BUCKET_BITMAP, ByteBuffer.class, Bitmap.class, byteBufferBitmapDecoder)
.append(Registry.BUCKET_BITMAP, InputStream.class, Bitmap.class, streamBitmapDecoder)
.append(
Registry.BUCKET_BITMAP,
ParcelFileDescriptor.class,
Bitmap.class,
parcelFileDescriptorVideoDecoder)
.append(
Registry.BUCKET_BITMAP,
AssetFileDescriptor.class,
Bitmap.class,
VideoDecoder.asset(bitmapPool))
.append(Bitmap.class, Bitmap.class, UnitModelLoader.Factory.<Bitmap>getInstance())
.append(
Registry.BUCKET_BITMAP, Bitmap.class, Bitmap.class, new UnitBitmapDecoder())
.append(Bitmap.class, bitmapEncoder)
/* BitmapDrawables */
.append(
Registry.BUCKET_BITMAP_DRAWABLE,
ByteBuffer.class,
BitmapDrawable.class,
new BitmapDrawableDecoder<>(resources, byteBufferBitmapDecoder))
.append(
Registry.BUCKET_BITMAP_DRAWABLE,
InputStream.class,
BitmapDrawable.class,
new BitmapDrawableDecoder<>(resources, streamBitmapDecoder))
.append(
Registry.BUCKET_BITMAP_DRAWABLE,
ParcelFileDescriptor.class,
BitmapDrawable.class,
new BitmapDrawableDecoder<>(resources, parcelFileDescriptorVideoDecoder))
.append(BitmapDrawable.class, new BitmapDrawableEncoder(bitmapPool, bitmapEncoder))
/* GIFs */
.append(
Registry.BUCKET_GIF,
InputStream.class,
GifDrawable.class,
new StreamGifDecoder(registry.getImageHeaderParsers(), byteBufferGifDecoder, arrayPool))
.append(Registry.BUCKET_GIF, ByteBuffer.class, GifDrawable.class, byteBufferGifDecoder)
.append(GifDrawable.class, new GifDrawableEncoder())
/* GIF Frames */
// Compilation with Gradle requires the type to be specified for UnitModelLoader here.
.append(
GifDecoder.class, GifDecoder.class, UnitModelLoader.Factory.<GifDecoder>getInstance())
.append(
Registry.BUCKET_BITMAP,
GifDecoder.class,
Bitmap.class,
new GifFrameResourceDecoder(bitmapPool))
/* Drawables */
.append(Uri.class, Drawable.class, resourceDrawableDecoder)
.append(
Uri.class, Bitmap.class, new ResourceBitmapDecoder(resourceDrawableDecoder, bitmapPool))
/* Files */
.register(new ByteBufferRewinder.Factory())
.append(File.class, ByteBuffer.class, new ByteBufferFileLoader.Factory())
.append(File.class, InputStream.class, new FileLoader.StreamFactory())
.append(File.class, File.class, new FileDecoder())
.append(File.class, ParcelFileDescriptor.class, new FileLoader.FileDescriptorFactory())
// Compilation with Gradle requires the type to be specified for UnitModelLoader here.
.append(File.class, File.class, UnitModelLoader.Factory.<File>getInstance())
/* Models */
.register(new InputStreamRewinder.Factory(arrayPool))
.append(int.class, InputStream.class, resourceLoaderStreamFactory)
.append(
int.class,
ParcelFileDescriptor.class,
resourceLoaderFileDescriptorFactory)
.append(Integer.class, InputStream.class, resourceLoaderStreamFactory)
.append(
Integer.class,
ParcelFileDescriptor.class,
resourceLoaderFileDescriptorFactory)
.append(Integer.class, Uri.class, resourceLoaderUriFactory)
.append(
int.class,
AssetFileDescriptor.class,
resourceLoaderAssetFileDescriptorFactory)
.append(
Integer.class,
AssetFileDescriptor.class,
resourceLoaderAssetFileDescriptorFactory)
.append(int.class, Uri.class, resourceLoaderUriFactory)
.append(String.class, InputStream.class, new DataUrlLoader.StreamFactory())
.append(String.class, InputStream.class, new StringLoader.StreamFactory())
.append(String.class, ParcelFileDescriptor.class, new StringLoader.FileDescriptorFactory())
.append(
String.class, AssetFileDescriptor.class, new StringLoader.AssetFileDescriptorFactory())
.append(Uri.class, InputStream.class, new HttpUriLoader.Factory())
.append(Uri.class, InputStream.class, new AssetUriLoader.StreamFactory(context.getAssets()))
.append(
Uri.class,
ParcelFileDescriptor.class,
new AssetUriLoader.FileDescriptorFactory(context.getAssets()))
.append(Uri.class, InputStream.class, new MediaStoreImageThumbLoader.Factory(context))
.append(Uri.class, InputStream.class, new MediaStoreVideoThumbLoader.Factory(context))
.append(
Uri.class,
InputStream.class,
new UriLoader.StreamFactory(contentResolver))
.append(
Uri.class,
ParcelFileDescriptor.class,
new UriLoader.FileDescriptorFactory(contentResolver))
.append(
Uri.class,
AssetFileDescriptor.class,
new UriLoader.AssetFileDescriptorFactory(contentResolver))
.append(Uri.class, InputStream.class, new UrlUriLoader.StreamFactory())
.append(URL.class, InputStream.class, new UrlLoader.StreamFactory())
.append(Uri.class, File.class, new MediaStoreFileLoader.Factory(context))
.append(GlideUrl.class, InputStream.class, new HttpGlideUrlLoader.Factory())
.append(byte[].class, ByteBuffer.class, new ByteArrayLoader.ByteBufferFactory())
.append(byte[].class, InputStream.class, new ByteArrayLoader.StreamFactory())
.append(Uri.class, Uri.class, UnitModelLoader.Factory.<Uri>getInstance())
.append(Drawable.class, Drawable.class, UnitModelLoader.Factory.<Drawable>getInstance())
.append(Drawable.class, Drawable.class, new UnitDrawableDecoder())
/* Transcoders */
.register(
Bitmap.class,
BitmapDrawable.class,
new BitmapDrawableTranscoder(resources))
.register(Bitmap.class, byte[].class, bitmapBytesTranscoder)
.register(
Drawable.class,
byte[].class,
new DrawableBytesTranscoder(
bitmapPool, bitmapBytesTranscoder, gifDrawableBytesTranscoder))
.register(GifDrawable.class, byte[].class, gifDrawableBytesTranscoder);
}
我們這時候發(fā)現(xiàn)，在new Glide的時候，它會去注冊一系列類放到List集合entries,之后取出他們調(diào)用build。
- 注釋②，我們主要是想知道網(wǎng)絡(luò)請求的時候有沒有添加User-Agent，從上面命名中，我們很容易關(guān)注到HttpUriLoader，那么我們就看看它的build方法都干了啥
public class HttpUriLoader implements ModelLoader<Uri, InputStream> {
public HttpUriLoader(ModelLoader<GlideUrl, InputStream> urlLoader) {
this.urlLoader = urlLoader;
}
public static class Factory implements ModelLoaderFactory<Uri, InputStream> {
public ModelLoader<Uri, InputStream> build(MultiModelLoaderFactory multiFactory) {
return new HttpUriLoader(multiFactory.build(GlideUrl.class, InputStream.class));
}
}
}
實際最終會調(diào)用HttpUriLoader的buildLoadData方法
@Override
public LoadData<InputStream> buildLoadData(@NonNull Uri model, int width, int height,
@NonNull Options options) {
return urlLoader.buildLoadData(new GlideUrl(model.toString()), width, height, options);
}
public GlideUrl(String url) {
this(url, Headers.DEFAULT);
}
Headers DEFAULT = new LazyHeaders.Builder().build();
最終我們走到了創(chuàng)建LazyHeaders對象
public static final class Builder {
private static final String USER_AGENT_HEADER = "User-Agent";
private static final String DEFAULT_USER_AGENT = getSanitizedUserAgent();
private static final Map<String, List<LazyHeaderFactory>> DEFAULT_HEADERS;
// Set Accept-Encoding header to do our best to avoid gzip since it's both inefficient for
// images and also makes it more difficult for us to detect and prevent partial content
// rendering. See #440.
static {
Map<String, List<LazyHeaderFactory>> temp
= new HashMap<>(2);
if (!TextUtils.isEmpty(DEFAULT_USER_AGENT)) {
temp.put(USER_AGENT_HEADER,
Collections.<LazyHeaderFactory>singletonList(
new StringHeaderFactory(DEFAULT_USER_AGENT)));
}
DEFAULT_HEADERS = Collections.unmodifiableMap(temp);
}
public Builder addHeader(String key, String value) {
return addHeader(key, new StringHeaderFactory(value));
}
public Builder addHeader(String key, LazyHeaderFactory factory) {
if (isUserAgentDefault && USER_AGENT_HEADER.equalsIgnoreCase(key)) {
return setHeader(key, factory);
}
copyIfNecessary();
getFactories(key).add(factory);
return this;
}
public Builder setHeader(String key, LazyHeaderFactory factory) {
copyIfNecessary();
if (factory == null) {
headers.remove(key);
} else {
List<LazyHeaderFactory> factories = getFactories(key);
factories.clear();
factories.add(factory);
}
if (isUserAgentDefault && USER_AGENT_HEADER.equalsIgnoreCase(key)) {
isUserAgentDefault = false;
}
return this;
}
}
我們發(fā)現(xiàn)LazyHeaders在創(chuàng)建的時候就已經(jīng)默認(rèn)添加了User-Agent
那么想要替換或者刪除User-Agent怎么做呢？我們看setHeader源碼，當(dāng)我們設(shè)置factory為null，則會直接移除，創(chuàng)建新的LazyHeaderFactory則直接替換
實戰(zhàn)與總結(jié)
實戰(zhàn)替換User-Agent
GlideUrl glideUrl = new GlideUrl(url1,new LazyHeaders.Builder().addHeader("User-Agent","android").build());
Glide.with(imageView.getContext().getApplicationContext()).asDrawable().load(glideUrl).apply(requestOptions).into(imageView);
總結(jié)
- 整體來說代碼還是相當(dāng)簡單的，主要就是要熟悉源碼
- glide加載圖片默認(rèn)用的是HttpUrlConnection，當(dāng)然它其實還有個庫，可以替換成okhttp。
- 加載網(wǎng)絡(luò)圖片的時候，默認(rèn)是在GlideUrl中設(shè)置了Headers.DEFAULT，它的內(nèi)部會在static中添加默認(rèn)的User-Agent。
