Java tutorial
/* Android Asynchronous Http Client Copyright (c) 2011 James Smith <james@loopj.com> http://loopj.com Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */ package com.lfrj.diancan.http; import android.util.Log; import org.apache.http.Header; import org.apache.http.HttpEntity; import org.apache.http.message.BasicHeader; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.HashMap; import java.util.Locale; import java.util.Map; import java.util.Set; import java.util.zip.GZIPOutputStream; /** * HTTP entity to upload JSON data using streams. This has very low memory * footprint; suitable for uploading large files using base64 encoding. */ public class JsonStreamerEntity implements HttpEntity { private static final String LOG_TAG = "JsonStreamerEntity"; private static final UnsupportedOperationException ERR_UNSUPPORTED = new UnsupportedOperationException( "Unsupported operation in this implementation."); // Size of the byte-array buffer used in I/O streams. private static final int BUFFER_SIZE = 4096; // Buffer used for reading from input streams. private final byte[] buffer = new byte[BUFFER_SIZE]; // Reusable StringBuilder used by escape() method. // Its size is just initial, if more space is needed, the system will // automatically enlarge the buffer. private static final StringBuilder BUILDER = new StringBuilder(128); private static final byte[] JSON_TRUE = "true".getBytes(); private static final byte[] JSON_FALSE = "false".getBytes(); private static final byte[] JSON_NULL = "null".getBytes(); private static final byte[] STREAM_NAME = escape("name"); private static final byte[] STREAM_TYPE = escape("type"); private static final byte[] STREAM_CONTENTS = escape("contents"); private static final byte[] STREAM_ELAPSED = escape("_elapsed"); private static final Header HEADER_JSON_CONTENT = new BasicHeader(AsyncHttpClient.HEADER_CONTENT_TYPE, RequestParams.APPLICATION_JSON); private static final Header HEADER_GZIP_ENCODING = new BasicHeader(AsyncHttpClient.HEADER_CONTENT_ENCODING, AsyncHttpClient.ENCODING_GZIP); // JSON data and associated meta-data to be uploaded. private final Map<String, Object> jsonParams = new HashMap<String, Object>(); // Whether to use gzip compression while uploading private final Header contentEncoding; private final ResponseHandlerInterface progressHandler; public JsonStreamerEntity(ResponseHandlerInterface progressHandler, boolean useGZipCompression) { this.progressHandler = progressHandler; this.contentEncoding = useGZipCompression ? HEADER_GZIP_ENCODING : null; } /** * Add content parameter, identified by the given key, to the request. * * @param key * entity's name * @param value * entity's value (Scalar, FileWrapper, StreamWrapper) */ public void addPart(String key, Object value) { jsonParams.put(key, value); } @Override public boolean isRepeatable() { return false; } @Override public boolean isChunked() { return false; } @Override public boolean isStreaming() { return false; } @Override public long getContentLength() { return -1; } @Override public Header getContentEncoding() { return contentEncoding; } @Override public Header getContentType() { return HEADER_JSON_CONTENT; } @Override public void consumeContent() throws IOException, UnsupportedOperationException { } @Override public InputStream getContent() throws IOException, UnsupportedOperationException { throw ERR_UNSUPPORTED; } @Override public void writeTo(final OutputStream out) throws IOException { if (out == null) { throw new IllegalStateException("Output stream cannot be null."); } // Record the time when uploading started. long now = System.currentTimeMillis(); // Use GZIP compression when sending streams, otherwise just use // a buffered output stream to speed things up a bit. OutputStream os = null != contentEncoding ? new GZIPOutputStream(out, BUFFER_SIZE) : out; // Always send a JSON object. os.write('{'); // Keys used by the HashMaps. Set<String> keys = jsonParams.keySet(); boolean isFileWrapper; // Go over all keys and handle each's value. for (String key : keys) { // Evaluate the value (which cannot be null). Object value = jsonParams.get(key); // Bail out prematurely if value's null. if (value == null) { continue; } // Write the JSON object's key. os.write(escape(key)); os.write(':'); // Check if this is a FileWrapper. isFileWrapper = value instanceof RequestParams.FileWrapper; // If a file should be uploaded. if (isFileWrapper || value instanceof RequestParams.StreamWrapper) { // All uploads are sent as an object containing the file's // details. os.write('{'); // Determine how to handle this entry. if (isFileWrapper) { writeToFromFile(os, (RequestParams.FileWrapper) value); } else { writeToFromStream(os, (RequestParams.StreamWrapper) value); } // End the file's object and prepare for next one. os.write('}'); } else if (value instanceof JsonValueInterface) { os.write(((JsonValueInterface) value).getEscapedJsonValue()); } else if (value instanceof org.json.JSONObject) { os.write(((org.json.JSONObject) value).toString().getBytes()); } else if (value instanceof org.json.JSONArray) { os.write(((org.json.JSONArray) value).toString().getBytes()); } else if (value instanceof Boolean) { os.write((Boolean) value ? JSON_TRUE : JSON_FALSE); } else if (value instanceof Long) { os.write((((Number) value).longValue() + "").getBytes()); } else if (value instanceof Double) { os.write((((Number) value).doubleValue() + "").getBytes()); } else if (value instanceof Float) { os.write((((Number) value).floatValue() + "").getBytes()); } else if (value instanceof Integer) { os.write((((Number) value).intValue() + "").getBytes()); } else { os.write(escape(value.toString())); } os.write(','); } // Include the elapsed time taken to upload everything. // This might be useful for somebody, but it serves us well since // there will almost always be a ',' as the last sent character. os.write(STREAM_ELAPSED); os.write(':'); long elapsedTime = System.currentTimeMillis() - now; os.write((elapsedTime + "}").getBytes()); Log.i(LOG_TAG, "Uploaded JSON in " + Math.floor(elapsedTime / 1000) + " seconds"); // Flush the contents up the stream. os.flush(); AsyncHttpClient.silentCloseOutputStream(os); } private void writeToFromStream(OutputStream os, RequestParams.StreamWrapper entry) throws IOException { // Send the meta data. writeMetaData(os, entry.name, entry.contentType); int bytesRead; // Upload the file's contents in Base64. Base64OutputStream bos = new Base64OutputStream(os, Base64.NO_CLOSE | Base64.NO_WRAP); // Read from input stream until no more data's left to read. while ((bytesRead = entry.inputStream.read(buffer)) != -1) { bos.write(buffer, 0, bytesRead); } // Close the Base64 output stream. AsyncHttpClient.silentCloseOutputStream(bos); // End the meta data. endMetaData(os); // Close input stream. if (entry.autoClose) { // Safely close the input stream. AsyncHttpClient.silentCloseInputStream(entry.inputStream); } } private void writeToFromFile(OutputStream os, RequestParams.FileWrapper wrapper) throws IOException { // Send the meta data. writeMetaData(os, wrapper.file.getName(), wrapper.contentType); int bytesRead, bytesWritten = 0, totalSize = (int) wrapper.file.length(); // Open the file for reading. FileInputStream in = new FileInputStream(wrapper.file); // Upload the file's contents in Base64. Base64OutputStream bos = new Base64OutputStream(os, Base64.NO_CLOSE | Base64.NO_WRAP); // Read from file until no more data's left to read. while ((bytesRead = in.read(buffer)) != -1) { bos.write(buffer, 0, bytesRead); bytesWritten += bytesRead; progressHandler.sendProgressMessage(bytesWritten, totalSize); } // Close the Base64 output stream. AsyncHttpClient.silentCloseOutputStream(bos); // End the meta data. endMetaData(os); // Safely close the input stream. AsyncHttpClient.silentCloseInputStream(in); } private void writeMetaData(OutputStream os, String name, String contentType) throws IOException { // Send the streams's name. os.write(STREAM_NAME); os.write(':'); os.write(escape(name)); os.write(','); // Send the streams's content type. os.write(STREAM_TYPE); os.write(':'); os.write(escape(contentType)); os.write(','); // Prepare the file content's key. os.write(STREAM_CONTENTS); os.write(':'); os.write('"'); } private void endMetaData(OutputStream os) throws IOException { os.write('"'); } // Curtosy of Simple-JSON: http://goo.gl/XoW8RF // Changed a bit to suit our needs in this class. static byte[] escape(String string) { // If it's null, just return prematurely. if (string == null) { return JSON_NULL; } // Surround with quotations. BUILDER.append('"'); int length = string.length(), pos = -1; while (++pos < length) { char ch = string.charAt(pos); switch (ch) { case '"': BUILDER.append("\\\""); break; case '\\': BUILDER.append("\\\\"); break; case '\b': BUILDER.append("\\b"); break; case '\f': BUILDER.append("\\f"); break; case '\n': BUILDER.append("\\n"); break; case '\r': BUILDER.append("\\r"); break; case '\t': BUILDER.append("\\t"); break; default: // Reference: http://www.unicode.org/versions/Unicode5.1.0/ if ((ch >= '\u0000' && ch <= '\u001F') || (ch >= '\u007F' && ch <= '\u009F') || (ch >= '\u2000' && ch <= '\u20FF')) { String intString = Integer.toHexString(ch); BUILDER.append("\\u"); int intLength = 4 - intString.length(); for (int zero = 0; zero < intLength; zero++) { BUILDER.append('0'); } BUILDER.append(intString.toUpperCase(Locale.US)); } else { BUILDER.append(ch); } break; } } // Surround with quotations. BUILDER.append('"'); try { return BUILDER.toString().getBytes(); } finally { // Empty the String buffer. // This is 20-30% faster than instantiating a new object. BUILDER.setLength(0); } } }