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5 Minutes on Adobe Flex: Mimic file upload for in-memory contents …

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Ever imagined uploading a file without using FileReference.upload?

In a web-app, access to filesystem is restricted, and at times, there is no need to refer to a file.  However, there may be situation where there is need to persist in-memory contents on servers.

The idea is to send contents from internal buffer which are non-file reference objects.  The fundamental behind  this is to fill in the content headers and mimic fileupload using HTTPService and here is the snippet for spoofing it.

Remember, though one can spoof the file upload, the trigger must be coming from an UI object (like a Button click event), otherwise, Flash will fail to upload the content.

public function spoofFileUpload(inputText:String,
 fileName:String,
 resultHandler:Function,
 faultHander:Function=null):void {

 var boundary:String = UIDUtil.createUID();
 var service:HTTPService = new HTTPService();

 service.url = SOME_SERVER_URI_ACCEPTING_FILE;
 service.method = "POST";
 service.contentType = "multipart/form-data; boundary=—————————" + boundary;

 var content:String = "—————————" + boundary + "nr";
 content += 'Content-Disposition: form-data; name="uploadfile"; filename="' + fileName + '";' + "nr";
 content += 'Content-Type: text/plain' + "nrnr";
 content += inputText + "nr";
 content += "—————————" + boundary + "nr";
 content += 'Content-Disposition: form-data; name="Submit"' + "nr" + "Submit" + "nr";
 content += "—————————–" + boundary + "–nr";

 service.request = content;
 service.resultFormat = HTTPService.RESULT_FORMAT_E4X;

 if(faultHander != null){
 service.addEventListener(FaultEvent.FAULT, faultHander);
 }

 if(resultHandler != null){
 service.addEventListener(ResultEvent.RESULT,
 function httpResult(event:ResultEvent):void
 {
 var xml:XML = XML(event.result);
 trace("SERVER RESPONSE: " + xml);
 // Invoke your result handler here
 resultHandler(xml);
 }
 );
 }

 // Send Request
 service.send();
}
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One thought on “5 Minutes on Adobe Flex: Mimic file upload for in-memory contents …

  1. Hi there can you please help me understand your multipart/form-data example?
    1) What is “nr” there?
    2) is undeerscore before boundry really required?

    I am trying something similar but have problem in making it work,
    I have posted my problem, here on stackoverflow

    http://stackoverflow.com/questions/12712433/multipart-form-data-flex-httpservice-uploading-a-file

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