How to pipe InputStream to ProcessBuilder
Please move down to the 2nd update. I didn't want to change the previous context of this question.
I'm using wkhtmltoimage from a Java app.
The standard way of using it is - path-to-exe http://url.com/ image.png.
According to their docs, if we write a - instead of an input URL, the input shifts to STDIN.
I'm starting the process using ProcessBuilder -
ProcessBuilder pb = new ProcessBuilder(exe_path, " - ", image_save_path);
Process process = pb.start();
Now I'm unable to figure out how to pipe an input stream to this process.
I have a template file read into a DataInputStream, and I'm appending a string at the end:
DataInputStream dis = new DataInputStream (new FileInputStream (currentDirectory+"\\bin\\template.txt"));
byte[] datainBytes = new byte[dis.available()];
dis.readFully(datainBytes);
dis.close();
String content = new String(datainBytes, 0, datainBytes.length);
content+=" <body><div id='chartContainer'><small>Loading chart...</small></div></body></html>";
How do I pipe content to the STDIN of the process?
UPDATE---
Following the answer by Andrzej Doyle:
I've used the getOutputStream() of the process:
ProcessBuilder pb = new ProcessBuilder(full_path, " - ", image_save_path);
pb.redirectErrorStream(true);
Process process = pb.start();
System.out.println("reading");
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(process.getOutputStream()));
bw.write(content);
Doing so gives an error saying:
Exception in thread "main" java.io.IOException: The pipe has been ended
2nd UPDATE--------
The current code block is as such:
try {
ProcessBuilder pb = new ProcessBuilder(full_path, "--crop-w", width, "--crop-h", height, " - ", image_save_path);
System.out.print(full_path+ "--crop-w"+ width+ "--crop-h"+ height+" "+ currentDirectory+"temp.html "+ image_save_path + " ");
pb.redirectErrorStream(true);
Process process = pb.start();
process.waitFor();
OutputStream stdin = process.getOutputStream();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(stdin));
// content is the string that I want to write to the process.
writer.write(content);
writer.newLine();
writer.flush();
writer.close();
} catch (Exception e) {
System.out.println("Exception: " + e);
e.printStackTrace();
}
Running the above code gives me an IOException: The pipe is being closed.
What else do I need to do to keep the pipe open?
Answer
Exception in thread "main" java.io.IOException: The pipe has been ended
This means the process you have started has died. I suggest you read the output to see why. e.g. did it give you an error.