Mercurial > hg > LGServices
view src/main/java/de/mpiwg/gazetteer/dataverse/MultipartUtility.java @ 4:c30ff4f27ec3
adding developer guide documentation
author | "jurzua <jurzua@mpiwg-berlin.mpg.de>" |
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date | Mon, 18 May 2015 15:55:01 +0200 |
parents | 3e62083dbcbf |
children |
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package de.mpiwg.gazetteer.dataverse; import java.io.BufferedReader; import java.io.ByteArrayInputStream; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.io.PrintWriter; import java.net.HttpURLConnection; import java.net.URL; import java.net.URLConnection; import java.nio.charset.Charset; import java.nio.charset.StandardCharsets; public class MultipartUtility { private final String boundary; private static final String LINE_FEED = "\r\n"; private HttpURLConnection httpConn; private String charset; private OutputStream outputStream; private PrintWriter writer; /** * This constructor initializes a new HTTP POST request with content type * is set to multipart/form-data * @param requestURL * @param charset * @throws IOException */ public MultipartUtility(String requestURL, String charset) throws IOException { this.charset = charset; // creates a unique boundary based on time stamp boundary = "===" + System.currentTimeMillis() + "==="; URL url = new URL(requestURL); httpConn = (HttpURLConnection) url.openConnection(); httpConn.setUseCaches(false); httpConn.setDoOutput(true); // indicates POST method httpConn.setDoInput(true); httpConn.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary); //httpConn.setRequestProperty("User-Agent", "CodeJava Agent"); outputStream = httpConn.getOutputStream(); writer = new PrintWriter(new OutputStreamWriter(outputStream, charset), true); } /** * Adds a form field to the request * @param name field name * @param value field value */ public void addFormField(String name, String value) { writer.append("--" + boundary).append(LINE_FEED); writer.append("Content-Disposition: form-data; name=\"" + name + "\"") .append(LINE_FEED); writer.append("Content-Type: text/plain; charset=" + charset).append( LINE_FEED); writer.append(LINE_FEED); writer.append(value).append(LINE_FEED); writer.flush(); } /** * Adds a upload file section to the request * @param fieldName name attribute in <input type="file" name="..." /> * @param uploadFile a File to be uploaded * @throws IOException */ public void addFilePart(String fieldName, File uploadFile) throws IOException { String fileName = uploadFile.getName(); writer.append("--" + boundary).append(LINE_FEED); writer.append( "Content-Disposition: form-data; name=\"" + fieldName + "\"; filename=\"" + fileName + "\"") .append(LINE_FEED); writer.append( "Content-Type: " + URLConnection.guessContentTypeFromName(fileName)) .append(LINE_FEED); writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED); writer.append(LINE_FEED); writer.flush(); FileInputStream inputStream = new FileInputStream(uploadFile); byte[] buffer = new byte[4096]; int bytesRead = -1; while ((bytesRead = inputStream.read(buffer)) != -1) { outputStream.write(buffer, 0, bytesRead); } outputStream.flush(); inputStream.close(); writer.append(LINE_FEED); writer.flush(); } public void addFilePart0(String fieldName, String fileContent) throws IOException { writer.append("--" + boundary).append(LINE_FEED); writer.append( "Content-Disposition: form-data; name=\"" + fieldName + "\"; filename=\"" + fieldName + "\"") .append(LINE_FEED); writer.append( "Content-Type: " + URLConnection.guessContentTypeFromName(fieldName)) .append(LINE_FEED); writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED); writer.append(LINE_FEED); writer.flush(); InputStream inputStream = new ByteArrayInputStream(fileContent.getBytes(StandardCharsets.UTF_8)); byte[] buffer = new byte[4096]; int bytesRead = -1; while ((bytesRead = inputStream.read(buffer)) != -1) { outputStream.write(buffer, 0, bytesRead); } outputStream.flush(); inputStream.close(); writer.append(LINE_FEED); writer.flush(); } /** * Adds a header field to the request. * @param name - name of the header field * @param value - value of the header field */ public void addHeaderField(String name, String value) { writer.append(name + ": " + value).append(LINE_FEED); writer.flush(); } /** * Completes the request and receives response from the server. * @return a list of Strings as response in case the server returned * status OK, otherwise an exception is thrown. * @throws IOException */ public String finish() throws IOException { StringBuilder sb = new StringBuilder(); writer.append(LINE_FEED).flush(); writer.append("--" + boundary + "--").append(LINE_FEED); writer.close(); // checks server's status code first int status = httpConn.getResponseCode(); if (status == HttpURLConnection.HTTP_OK) { BufferedReader reader = new BufferedReader(new InputStreamReader( httpConn.getInputStream())); String line = null; while ((line = reader.readLine()) != null) { sb.append(line); } reader.close(); httpConn.disconnect(); } else { throw new IOException("Server returned non-OK status: " + status); } return sb.toString(); } }