I am attempting to upload a file from my Android app to the Flask server. The logcat on Android Studio shows I/uploadFile: HTTP Response is : OK: 200 but I am unable to see the uploaded file on the server.
Following is my flask code which I have referred to from http://flask.pocoo.org/docs/0.12/patterns/fileuploads/:
import os
from flask import Flask, request, redirect, url_for, jsonify
from werkzeug.utils import secure_filename
UPLOAD_FOLDER = '/Users/Vishwak/PycharmProjects/BraiNet/'
ALLOWED_EXTENSIONS = {'txt', 'pdf', 'png', 'jpg', 'jpeg', 'gif'}
app = Flask(__name__)
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
def allowed_file(filename):
return '.' in filename and \
filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS
@app.route('/', methods=['GET', 'POST'])
def upload_file():
if request.method == 'POST':
print request
print request.values
# check if the post request has the file part
if 'file' not in request.files:
# flash('No file part')
return redirect(request.url)
print(request.files['file'])
file = request.files['file']
# if user does not select file, browser also
# submit a empty part without filename
if file.filename == '':
print(file)
# flash('No selected file')
return redirect(request.url)
if file and allowed_file(file.filename):
print(file)
print(file.filename)
filename = secure_filename(file.filename)
# print filename
print(app.config['UPLOAD_FOLDER'])
file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
return redirect(url_for('upload_file',
filename=filename))
return '''
<!doctype html>
<title>Upload new File</title>
<h1>Upload new File</h1>
<form method=post enctype=multipart/form-data>
<p><input type=file name=file>
<input type=submit value=Upload>
</form>
'''
if __name__ == '__main__':
app.run()
This works as expected when I upload a file using the Web interface and I can view the file on the server.
The problem arises when I try to upload the file from the Android app. Here is the java code:
private class UploadTask extends AsyncTask { private Context context;
public UploadTask(Context context) {
this.context = context;
}
@Override
protected String doInBackground(String... params) {
String fileName =path;
String fileName2=path.substring(path.lastIndexOf("/")+1);
String fileName4 = fileName2.substring(0, fileName2.lastIndexOf("."));
HttpURLConnection conn = null;
DataOutputStream dos = null;
String lineEnd = "\r\n";
String twoHyphens = "--";
String boundary = "*****";
int bytesRead, bytesAvailable, bufferSize;
byte[] buffer;
int maxBufferSize = 1 * 1024 * 1024;
File sourceFile = new File(fileName);
if (!sourceFile.isFile()) {
Log.e("uploadFile", "Source File not exist :"
+ uri);
runOnUiThread(new Runnable() {
public void run() {
// messageText.setText("Source File not exist :"
// +uploadFilePath + "" + uploadFileName);
}
});
} else {
try {
// open a URL connection to the Servlet
FileInputStream fileInputStream = new FileInputStream(sourceFile);
// System.out.println(Array.toString(fileInputStream));
URL url = new URL(upLoadServerUri);
// Open a HTTP connection to the URL
conn = (HttpURLConnection) url.openConnection();
conn.setDoInput(true); // Allow Inputs
conn.setDoOutput(true); // Allow Outputs
conn.setUseCaches(false); // Dont use a Cached Copy
conn.setRequestMethod("POST");
conn.setRequestProperty("Connection", "Keep-Alive");
conn.setRequestProperty("ENCTYPE", "multipart/form-data");
conn.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
conn.setRequestProperty("uploaded_file", fileName);
dos = new DataOutputStream(conn.getOutputStream());
dos.writeBytes(twoHyphens + boundary + lineEnd);
dos.writeBytes("Content-Disposition: form-data; uploaded_file=uploaded_file ;filename=" + fileName + lineEnd);
// dos.writeBytes("Content-Disposition: form-data; name=" + fileName4 + ";filename=" + fileName2 + "" + lineEnd);
dos.writeBytes(lineEnd);
// create a buffer of maximum size
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
buffer = new byte[bufferSize];
// read file and write it into form...
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
while (bytesRead > 0) {
dos.write(buffer, 0, bufferSize);
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
}
// send multipart form data necesssary after file data...
dos.writeBytes(lineEnd);
dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
// Responses from the server (code and message)
serverResponseCode = conn.getResponseCode();
String serverResponseMessage = conn.getResponseMessage();
Log.i("uploadFile", "HTTP Response is : "
+ serverResponseMessage + ": " + serverResponseCode);
if (serverResponseCode == 200) {
runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(MainActivity.this, "File Upload Complete.",
Toast.LENGTH_SHORT).show();
}
});
}
//close the streams //
fileInputStream.close();
dos.flush();
dos.close();
}
catch (MalformedURLException ex) {
ex.printStackTrace();
runOnUiThread(new Runnable() {
public void run() {
// messageText.setText("MalformedURLException Exception : check script url.");
Toast.makeText(MainActivity.this, "MalformedURLException",
Toast.LENGTH_SHORT).show();
}
});
Log.e("Upload file to server", "error: " + ex.getMessage(), ex);
}
catch (Exception e) {
e.printStackTrace();
runOnUiThread(new Runnable() {
public void run() {
// messageText.setText("Got Exception : see logcat ");
Toast.makeText(MainActivity.this, "Got Exception : see logcat ",
Toast.LENGTH_SHORT).show();
}
});
Log.e("Upload Exception", "Exception:" + e.getMessage(), e);
}
}
return null;
} // End else block
I am a novice at Java and I don't really understand where I am going wrong in my Android code and what I will have to change to make this work.
Any feedback on changing the Flask or Android code will be greatly appreciated.
