Why I can't upload file to Google Cloud Storage that larger than 100KByte through app engine?
google-app-engine, google-cloud-storage, java
Solution
Try changing the second `is.read` from:
readBytes = is.read(b, 0, readBytes);
to:
readBytes = is.read(b, 0, BUFFER_SIZE);
If at some point you are reading faster then data is available, `readBytes` is set to `0` and it stays forever at this value, because it's basically doing `is.read(b, 0, 0)`.
Even better - you should check if there is data to be written:
while (readBytes != -1) {
if(readBytes > 0)
storage.storeFile(b, readBytes);
readBytes = is.read(b, 0, BUFFER_SIZE);
}
Problem
My project contains only simple file upload form and the redirect to view it. I can upload any files less than 50 KB but when I upload some files larger than 100 KB, it throws IO Exception from app engine. I am not sure where the problem is. Do anyone know how to increase the file size that I can upload to Google Cloud storage through the form posting in app engine? file size properly less than 10 MB is OK. Any code snippets would be vhighly appreciated. Thank you. ``` java.io.IOException at com.google.appengine.api.files.FileServiceImpl.translateException(FileServiceImpl.java:615) at com.google.appengine.api.files.FileServiceImpl.makeSyncCall(FileServiceImpl.java:588) at com.google.appengine.api.files.FileServiceImpl.append(FileServiceImpl.java:535) at com.google.appengine.api.files.FileServiceImpl.append(FileServiceImpl.java:289) at com.google.appengine.api.files.FileWriteChannelImpl.write(FileWriteChannelImpl.java:57) at com.google.appengine.api.files.FileWriteChannelImpl.write(FileWriteChannelImpl.java:46) at java.nio.channels.Channels.write(Channels.java:80) at java.nio.channels.Channels.access$000(Channels.java:64) at java.nio.channels.Channels$1.write(Channels.java:151) at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82) at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:140) at storefile.StorageService.storeFile(StorageService.java:46) at storefile.UploadServlet.doPost(UploadServlet.java:46) at javax.servlet.http.HttpServlet.service(HttpServlet.java:637) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) ``` Following is my code: upload.html ``` <html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <title>Hello App Engine</title> </head> <body> <h1>Hello App Engine!</h1> <form action="/upload" method="post" enctype="multipart/form-data"> <p>File<input type="file" name="file" /> </p> <p> <input type="submit"value="upload" /> <input type="reset" value="reset"/> </p> </form> </body> </html> ``` uploadServlet.java ``` import java.io.BufferedInputStream; import java.io.IOException; import java.io.InputStream; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.fileupload.FileItemIterator; import org.apache.commons.fileupload.FileItemStream; import org.apache.commons.fileupload.servlet.ServletFileUpload; import com.google.appengine.api.blobstore.BlobKey; public class UploadServlet extends HttpServlet{ private static final long serialVersionUID = 1L; private StorageService storage = new StorageService(); private static int BUFFER_SIZE =1024 * 1024* 10; @Override public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException { resp.setContentType("text/plain"); resp.getWriter().println("Now see here your file content, that you have uploaded on storage.."); ServletFileUpload upload = new ServletFileUpload(); FileItemIterator iter; try { iter = upload.getItemIterator(req); while (iter.hasNext()) { FileItemStream item = iter.next(); String fileName = item.getName(); String mime = item.getContentType(); storage.init(fileName, mime); InputStream is = new BufferedInputStream(item.openStream()); byte[] b = new byte[BUFFER_SIZE]; int readBytes = is.read(b, 0, BUFFER_SIZE); while (readBytes != -1) { storage.storeFile(b, readBytes); readBytes = is.read(b, 0, readBytes); } is.close(); storage.destroy(); resp.getWriter().println("File uploading done"); // resp.getWriter().println("READ:" + storage.readTextFileOnly(fileName)); BlobKey key = storage.getBlobkey(fileName); if (key != null) { resp.sendRedirect("/serve?blob-key=" + key.getKeyString()); } else { resp.sendRedirect("/"); } } } catch (Exception e) { e.printStackTrace(resp.getWriter()); System.out.println("Exception::"+e.getMessage()); e.printStackTrace(); } } } ``` StorageService.java ``` import java.io.BufferedOutputStream; import java.io.BufferedReader; import java.nio.channels.Channels; import java.util.logging.Logger; import com.google.appengine.api.blobstore.BlobKey; import com.google.appengine.api.blobstore.BlobstoreService; import com.google.appengine.api.blobstore.BlobstoreServiceFactory; import com.google.appengine.api.files.AppEngineFile; import com.google.appengine.api.files.FileReadChannel; import com.google.appengine.api.files.FileService; import com.google.appengine.api.files.FileServiceFactory; import com.google.appengine.api.files.FileWriteChannel; import com.google.appengine.api.files.GSFileOptions.GSFileOptionsBuilder; public class StorageService { public static final String BUCKET_NAME = "aaaa"; private FileWriteChannel writeChannel = null; FileService fileService = FileServiceFactory.getFileService(); private BufferedOutputStream bos = null; private static final Logger log = Logger.getLogger(StorageService.class.getName()); private BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService(); public void init(String fileName, String mime) throws Exception { System.out.println("Storage service:init() method: file name:"+fileName+" and mime:"+mime); log.info("Storage service:init() method: file name:"+fileName+" and mime:"+mime); GSFileOptionsBuilder builder = new GSFileOptionsBuilder() .setAcl("public_read") .setBucket(BUCKET_NAME) .setKey(fileName) .setMimeType(mime); AppEngineFile writableFile = fileService.createNewGSFile(builder.build()); boolean lock = true; writeChannel = fileService.openWriteChannel(writableFile, lock); bos = new BufferedOutputStream(Channels.newOutputStream(writeChannel)); } public void storeFile(byte[] b, int readSize) throws Exception { bos.write(b,0,readSize); bos.flush(); } public void destroy() throws Exception { log.info("Storage service: destroy() method"); bos.close(); writeChannel.closeFinally(); } public BlobKey getBlobkey (String filename) { BlobKey bk = blobstoreService.createGsBlobKey("/gs/aaaa/"+filename); return bk; } } ``` fileserve.java ``` import java.io.IOException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.google.appengine.api.blobstore.BlobKey; import com.google.appengine.api.blobstore.BlobstoreService; import com.google.appengine.api.blobstore.BlobstoreServiceFactory; public class fileserve extends HttpServlet { private BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService(); public void doGet(HttpServletRequest req, HttpServletResponse res) throws IOException { BlobKey blobKey = new BlobKey(req.getParameter("blob-key")); blobstoreService.serve(blobKey, res); } } ``` web.xml ``` <?xml version="1.0" encoding="utf-8" standalone="no"?><web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.5" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <servlet> <servlet-name>upload</servlet-name> <servlet-class>storefile.UploadServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>upload</servlet-name> <url-pattern>/upload</url-pattern> </servlet-mapping> <servlet> <servlet-name>serve</servlet-name> <servlet-class>storefile.fileserve</servlet-class> </servlet> <servlet-mapping> <servlet-name>serve</servlet-name> <url-pattern>/serve</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> ```