Thread-safe HTTP transport for Google App Engine based on URL Fetch.
Implementation is thread-safe. For maximum efficiency, applications should use a single
globally-shared instance of the HTTP transport.
URL Fetch is only available on Google App Engine (not on any other Java environment), and is
the underlying HTTP transport used for App Engine. Their implementation of HttpURLConnection is simply an abstraction layer on top of URL Fetch. By implementing a
transport that directly uses URL Fetch, we can optimize the behavior slightly, and can
potentially take advantage of features in URL Fetch that are not available in HttpURLConnection. Furthermore, there is currently a serious bug in how HTTP headers are
processed in the App Engine implementation of HttpURLConnection, which we are able to
avoid using this implementation. Therefore, this is the recommended transport to use on App
Engine.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-28 UTC."],[],[],null,["# Package com.google.api.client.extensions.appengine.http (2.0.0)\n\nVersion latestkeyboard_arrow_down\n\n- [2.0.0 (latest)](/java/docs/reference/google-http-client/latest/com.google.api.client.extensions.appengine.http)\n- [1.47.1](/java/docs/reference/google-http-client/1.47.1/com.google.api.client.extensions.appengine.http)\n- [1.46.3](/java/docs/reference/google-http-client/1.46.3/com.google.api.client.extensions.appengine.http)\n- [1.45.3](/java/docs/reference/google-http-client/1.45.3/com.google.api.client.extensions.appengine.http)\n- [1.44.2](/java/docs/reference/google-http-client/1.44.2/com.google.api.client.extensions.appengine.http)\n- [1.43.2](/java/docs/reference/google-http-client/1.43.2/com.google.api.client.extensions.appengine.http)\n- [1.42.3](/java/docs/reference/google-http-client/1.42.3/com.google.api.client.extensions.appengine.http)\n- [1.41.8](/java/docs/reference/google-http-client/1.41.8/com.google.api.client.extensions.appengine.http) \nHTTP Transport library for Google API's based on [URL Fetch in Google\nApp Engine](https://cloud.google.com/appengine/docs/standard/java/issue-requests).\n\nClasses\n-------\n\n### [UrlFetchTransport](/java/docs/reference/google-http-client/latest/com.google.api.client.extensions.appengine.http.UrlFetchTransport)\n\nThread-safe HTTP transport for Google App Engine based on [URL Fetch](https://cloud.google.com/appengine/docs/standard/java/issue-requests).\n\nImplementation is thread-safe. For maximum efficiency, applications should use a single\nglobally-shared instance of the HTTP transport.\n\nURL Fetch is only available on Google App Engine (not on any other Java environment), and is\nthe underlying HTTP transport used for App Engine. Their implementation of [HttpURLConnection](https://docs.oracle.com/javase/8/docs/api/java/net/HttpURLConnection.html) is simply an abstraction layer on top of URL Fetch. By implementing a\ntransport that directly uses URL Fetch, we can optimize the behavior slightly, and can\npotentially take advantage of features in URL Fetch that are not available in [HttpURLConnection](https://docs.oracle.com/javase/8/docs/api/java/net/HttpURLConnection.html). Furthermore, there is currently a serious bug in how HTTP headers are\nprocessed in the App Engine implementation of [HttpURLConnection](https://docs.oracle.com/javase/8/docs/api/java/net/HttpURLConnection.html), which we are able to\navoid using this implementation. Therefore, this is the recommended transport to use on App\nEngine.\n\n### [UrlFetchTransport.Builder](/java/docs/reference/google-http-client/latest/com.google.api.client.extensions.appengine.http.UrlFetchTransport.Builder)\n\nBuilder for [UrlFetchTransport](/java/docs/reference/google-http-client/latest/com.google.api.client.extensions.appengine.http.UrlFetchTransport).\n\nImplementation is not thread-safe."]]
