synapse httpserver send data and re-direct
lazarus / 38-Networking and Web Programming

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epergola · 2018-10-05 22:02

Hi
I have a small synapse http server. It uses TTCPBlockSocket.sendbuffer
(as in the example in the synapse directory) to send outputdata.
The outputdata is created this way:
        st := TFileStream.Create(filename, fmOpenRead or
fmShareDenyWrite);
                headers.add('--' + IntToHex(Random(MaxInt),  +
'_Synapse_boundary');
                headers.add('content-disposition: form-data; name="' +
filename + '";'
                  + ' filename="' + filename +'"');
                headers.add('Content-Type: Application/octet-string');
                outputdata.CopyFrom(st, 0);
And it will download the file "filename". This part works fine.
Now, I would like to also attach an html file to outputdata wich
should show up on the client (browser) with a thank you message. I
have the html file on disk. I can't find out how to make this work.
When I simply attach the file preceded by 'Content-Type: text/plain',
it gets attached but not loaded as a apage in the browser. Anybody
could give me a hint?

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sash · 2018-10-06 09:31

You need to display download page (with your thank-text and automatic
/ manual (anchor) download) instead.

To do so you need to (in a simplest way) handle request uri (to
distinguish between actual file or download page html).

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epergola · 2018-10-06 17:47

That "distinguish" is exaclty what I do not know how to implement.
I have a login page which the user fills. The HTTp server (uses a
TTCPBlockSocket, the bind() funcion and the ProcessHttpRequest
function as in the synapse example) sends a response. The response is
a report. This part works WELL (the browser downloads the file sent by
the server). Now I would like to send DATA+an html sequence so that
after (or while) downloads the browser opens up the html content.  I
do not know how to ATTACH the html to the data part to make show in
the browser.
I do what is show in the attachment, but what it does is that the html
content is physically send at the end of the data but is not displayed
in the browser. If I send the html part only (no data) it shows.

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sash · 2018-10-06 20:38

QuoteThat "distinguish" is exaclty what I do not know how to
implement. You need routing: server should check request headers - uri
http://wiki.freepascal.org/Networking#Webserver_example
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i   //
.........  //read request line  s := ASocket.RecvString(timeout); 
method := fetch(s, ' ');  uri := fetch(s, ' ');  protocol := fetch(s,
' ');  // ......... simplest routing  case uri of  'donwload' :
SendMyFile();  'donwload-page' : ShowDownloadPage();  end;QuoteNow I
would like to send DATA+an html sequence so that after (or while)
downloads the browser opens up the html contentYou cannot send TWO
entities (distinguishable by browser) in a single request-response
transaction. That's why I said you need to display download page as
(html). And from this page (by clicking link(anchor) or automatically)
new request (actual download) will be initiated.


Here's sample page where download will start automatically in 2 sec
after page loaded in browser.
Code: HTML5  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i <html
lang="en"><head>  <meta charset="utf-8">  <title>Thank you</title>  <!
--link rel="stylesheet" href="css/styles.css"--> </head> <iframe
id="download_iframe" style="display:none;"></iframe> <body
onload="autoDownload()">  <script>    var myDownload = '/download';  
    function autoDownload()    {      setTimeout(function(){       
//alert('Loaded');       
document.getElementById('download_iframe').src = myDownload;        },
2000      );    }  </script>    <h1>Congrats, here's your
download</h1>    <p>  Lorem ipsum dolor sit amet, consetetur
sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et
dolore magna aliquyam erat, sed diam voluptua.  </p>   </body></html> 

And please, learn how HTTP works (request, response, headers, content
type, method, response codes).