CODEWITHSUNDEEP
javascriptnode.js
ConfusedCoder
ConfusedCoder

Reputation: 33

Retrieving a value from a node child process

var fp = 'ffprobe ' + fileName + ' -show_streams | grep '
var width = exec(fp+'width', function(err, stdout, stderr){
    return stdout;
});
alert(stdout + 'random example');

how do I get the stdout 'out' of the process so that I can use it later.

Upvotes: 3

Views: 5014

Answers (4)

moeiscool
moeiscool

Reputation: 1426

None of the answers above worked for me. This did though.

var probeCommand = 'rtsp://xx.xx.xx.xx/axis-media/media.3gp'
exec('ffprobe '+probeCommand+' | echo ',function(err,stdout,stderr){
    console.log(stdout+stderr)
})

Upvotes: 0

Jon Gauthier
Jon Gauthier

Reputation: 25572

Node's exec function is asynchronous. This means that there is no guarantee that code below the exec call will wait until the child process finishes to run. To execute code once the process quits, then, you must provide a callback which deals with the results. Your code can branch off from there:

var fp = 'ffprobe ' + fileName + ' -show_streams | grep ';
var width = exec(fp+'width', function(err, stdout, stderr){
    console.log(stdout);

    // ... process stdout a bit ...

    afterFFProbe(stdout);
});

function afterFFProbe(output) {
    // your program continues here
}

Upvotes: 6

George Korac
George Korac

Reputation: 143

I think this might work: 

var output = "";
var fp = 'ffprobe ' + fileName + ' -show_streams | grep '
var width = exec(fp+'width', function(err, stdout, stderr){
this.output = stdout;
});
alert(output + 'random example');

Upvotes: -1

Jeremy
Jeremy

Reputation: 792

If I'm understanding you correctly:

var fp = 'ffprobe ' + fileName + ' -show_streams | grep ',
    value,
    width = exec(fp+'width', function(err, stdout, stderr) {
        value = stdout;
        return stdout;
    });
alert(value + 'random example');

Upvotes: -1

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