java - using curl with Runtime.getRuntime().exec

Question

I want to use curl within a java program using Runtime.getRuntime().exec

The full snippet is below yet what my problem boils down to is that I get an error response when I use the curl command in Runtime.getRuntime().exec(command) but when I System.out.println the command, copy and paste it to a shell and execute it there it works fine.

System.out.println(command);
Runtime.getRuntime().exec(command);

What could cause this different outcome between runtime exec and executing the command in the shell.

Thanks for any hints

martin

updates:

The error response I get when using Runtime is: {"error":"unauthorized"}
As I see from the commands that seems to be unclear. I dont get any Exception the curl command runs through but the json response is as posted above.

String APP_ID = "XXX";
String REST_API_KEY = "YYY";

String header = "-H \"X-Parse-Application-Id: " + APP_ID
        + "\" -H \"X-Parse-REST-API-Key: " + REST_API_KEY
        + "\" -H \"Content-Type: application/zip\" ";

public void post2Parse(String fileName) {

    String outputString;

    String command = "curl -X POST " + header + "--data-binary '@"
            + fileName + "' https://api.parse.com/1/files/" + fileName;

    System.out.println(command);

    Process curlProc;
    try {
        curlProc = Runtime.getRuntime().exec(command);

        DataInputStream curlIn = new DataInputStream(
                curlProc.getInputStream());

        while ((outputString = curlIn.readLine()) != null) {
            System.out.println(outputString);
        }

    } catch (IOException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }
}

do you get an exception? which errorcode and Message does it have? or is the output showing unauthorized? — CloudyMarble
– CloudyMarble, Commented Sep 17, 2012 at 5:30
my question is really more about what can make the difference between the Runtime.getRuntime().exec() command execution and executing the very same command in a shell — dorjeduck
– dorjeduck, Commented Sep 17, 2012 at 5:44

Community · Accepted Answer · 2017-05-23 12:34:33Z

4

I don't have a direct answer, but a bit on the way is that the apostrophe gets encoded differently. Although an old question, I'll answer to for future reference, and maybe someone can explain the complete answer later.

When I test our API in a similar way I notice the following:

curl -i http://localhost:8080/auth/login -d '[email protected]&password=test'

This command, when sent from shell, ends up in the server as:

[email protected],\npassword=test,\n

but when sent from Runtime.getRuntime().exec(command), it ends up as:

'[email protected],\npassword=test',\n

If I change the curl command and remove the apostrophes, it works (due to the essence of this command)

 curl -i http://localhost:8080/auth/login -d [email protected]&password=test

Thus a fait guess is that if the code in the question is changed to this, it may actually work if the file name contains no space...:

String command = "curl -X POST " + header + "--data-binary @"
        + fileName + " https://api.parse.com/1/files/" + fileName;

One option would be to use the execute command with an array of inputs as described here: Runtime Exec seems to be ignoring apostrophes In combination of parsing the curl command (unless hard coded) as described here: Split string on spaces in Java, except if between quotes (i.e. treat \"hello world\" as one token)

edited May 23, 2017 at 12:34

CommunityBot

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answered Nov 22, 2016 at 9:50

Andreas Lundgren

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1 Comment

Larusso Over a year ago

You saved my life sir. I banged my head a few hours against this wall. I wanted to simply upload a file with curl from gradle (As a quick implementation) That took way longer than expected Cheers!

Community · Accepted Answer · 2017-05-23 12:02:41Z

0

I guess you get an Errorcode from Curl not the exception, check the Curl API again, u guess you will find any missing parameter like "User" or other stuff.

You can try to check some of the hints mentioned in this answer.

edited May 23, 2017 at 12:02

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answered Sep 17, 2012 at 5:39

CloudyMarble

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2 Comments

dorjeduck Over a year ago

thanks - yes not an exception but an error response as mentioned . The very same curl command works when executed in a shell so it really doesnt seem to be a problem at that side of the Curl API...

dorjeduck Over a year ago

i saw this other post but for simplicity i decided to go for Runtime as suggested in one comments there

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