how to rewrite html body

[dabeike]

how to change the contents of html,when the page is received from proxy?
my aim is to add some html code to the page,when the page returns to client
the code is like followings:

proxy.on('proxyRes', function (proxyRes, request, response){
     proxyRes.on('end',function(){
            if(proxyRes.headers['content-type']=='text/html;charset=utf-8'){
                proxyRes.write('hhhhhhhhhhh');   //this sentence may be wrong
            }
        })
})

[betlab]

+1

[kokarn]

I'm not at all sure what's the best way to do this, but this is a scrip we've used successfully to inject a script into a page.

var scriptElm = '<script src="test.js"></script>';

function modifyHtml( str ) {
    // Add or script to the page
    if( str.indexOf( '</body>' ) > -1 ) {
        str = str.replace( '</body>', scriptElm + '</body>' );
    } else if ( str.indexOf( '</html>' ) > -1 ){
        str = str.replace( '</html>', scriptElm + '</html>' );
    } else {
        str = str + scriptElm;
    }

    return str;
}

proxy.on( 'proxyRes', function ( proxyRes, request, response ) {
    if( proxyRes.headers &&
        proxyRes.headers[ 'content-type' ] &&
        proxyRes.headers[ 'content-type' ].match( 'text/html' ) ) {

        var _end = response.end,
            chunks,
            _writeHead = response.writeHead;

        response.writeHead = function(){
            if( proxyRes.headers && proxyRes.headers[ 'content-length' ] ){
                response.setHeader(
                    'content-length',
                    parseInt( proxyRes.headers[ 'content-length' ], 10 ) + scriptElm.length
                );
            }

            // This disables chunked encoding
            response.setHeader( 'transfer-encoding', '' );

            // Disable cache for all http as well
            response.setHeader( 'cache-control', 'no-cache' );

            _writeHead.apply( this, arguments );
        };

        response.write = function( data ) {
            if( chunks ) {
                chunks += data;
            } else {
                chunks = data;
            }
        };

        response.end = function() {
            if( chunks && chunks.toString ) {
                _end.apply( response, [ modifyHtml( chunks.toString() ) ] );
            } else {
                _end.apply( response, arguments );
            }
        };
    }
});

[xtof78]

This solution must be modified to avoid the use of end( ... modify ) which uses implicilty the write() method which has been rerouted into collecting the chunks. So you finish having another chunk which is your own.

Fix:

        var _write = response.write;

...

        response.end = function() {
            if( chunks && chunks.toString )
                _write.apply( this, [ modifyHtml( chunks.toString() ) ] );
            _end.apply( this, arguments );
       };

[macscripter]

Question, I would like to do the same but for request. That's, before proxyng, I need to put an extra parameter to the body and after proxy the request. How can I do it?

[xingshijie]

Maybe this method is right for you

proxy.on('proxyRes', function (proxyRes, req, res) {
    var body = new Buffer('test body');
    proxyRes.pipe = function (res) {
      res.write(body)
      res.end()
    }
})

[xianshenglu]

This works for me. https://github.com/saskodh/http-proxy-response-rewrite