Cognitive Service Container Proxy Example

CognitiveServiceContainerProxyExample.js

// Cognitive Service containers don't currently handle Cross-origin resource sharing (CORS) headers.  This means that for user agents
// that enforce CORS (browsers, typically), requests will fail.  The following code is an example of how you might work around this,
// temporarily, until the containers are fixed.  This code is provided as-is, with no guarantees.
//
// The following is a modified version of code found here: https://github.com/ccoenraets/cors-proxy.

var express = require('express'),
    request = require('request'),
    bodyParser = require('body-parser'),
    app = express();

let ocrBase = 'http://localhost:5000'; // Adjust if necessary

app.use(bodyParser.raw({
    limit: '4MB',
    type: '*/*'
}));

app.all('*', function (req, res, next) {

    // Set CORS headers: allow all origins, methods, and headers: you may want to lock this down in a production environment
    res.header("Access-Control-Allow-Origin", "*");
    res.header("Access-Control-Allow-Methods", "GET, PUT, PATCH, POST, DELETE");
    res.header("Access-Control-Allow-Headers", req.header('access-control-request-headers'));

    if (req.method === 'OPTIONS') {
        // CORS Preflight
        res.send();
    } else {
        new_req = {
            url: ocrBase + req.url,
            method: req.method,
            query: req.query,
            headers: req.headers,
            body: req.body
        };
        request(new_req,
            function (error, response, body) {
                if (error) {
                    console.error('error: ' + response)
                }
            }).pipe(res);
    }
});

app.set('port', process.env.PORT || 3000);

app.listen(app.get('port'), function () {
    console.log('Proxy server listening on port ' + app.get('port'));
});

Thanks @cthrash!
I was getting some errors around req.headers['content-type'] since not all requests had content-type headers, but I was able to modify https://github.com/ccoenraets/cors-proxy with the help of this gist, as updated here: https://gist.github.com/AugustKarlstedt/fbe1a29d62f800de6a44a314c80af0ae

Thanks for the feedback. I've updated this gist based on your feedback. It should work if you chose to send the image in the payload, which your example won't do. This may not be important in your use case.

Fixed an error in new_req construction. Sorry about that!

Updated to handle other content types.

Awesome, thanks @cthrash!