Fiddler add binary file data to POST

Question

I'm try to add binary file data directly to the request body of a POST call so I can simulate a file upload. However, I tried setting a 'before request' breakpoint and using 'insert file' but I couldn't seem to get that to work. I also tried to modify CustomRules.js to inject the file but couldn't figure out how to load binary data via JScript. Is there an easy solution here?

Answer 1

I'm sure this is a new feature in the year since this question was answered, but thought I'd add it anyhow:

There's a blue "[Upload file]" link in Composer now on the right side under the URL textbox. This will create a full multipart/form-data request. If you use this, you'll notice in the body you now have something that looks like this:

<@INCLUDE C:\Some\Path\my-image.jpg@>

In my case, I just wanted to POST the binary file directly with no multipart junk, so I just put the <@INCLUDE ... @> magic in the request body, and that sends the binary file as the body.

Answer 2

In Fiddler script: (in Fiddler: Rules... Customize Rules), find the OnBeforeRequest function, and add a line similar to:

if (oSession.uriContains("yourdomain"))
{
    oSession.LoadRequestBodyFromFile("c:\\temp\\binarycontent.dat");    
}

Answer 3

In order to send multipart/form-data, this receipe will be helped.

In upper panel (Http header), set Content-Type as below. Other values are automatically resolved.

Content-Type: multipart/form-data; boundary=-------------------------acebdf13572468

And, input Response Body at the below panel as follows.

---------------------------acebdf13572468
Content-Disposition: form-data; name="description" 

the_text_is_here
---------------------------acebdf13572468
Content-Disposition: form-data; name="file"; filename="123.jpg"
Content-Type: image/jpg

<@INCLUDE *C:\Users\Me\Pictures\95111c18-e969-440c-81bf-2579f29b3564.jpg*@>
---------------------------acebdf13572468--

The import rules are,

1. Content-Type should have two more - signs than boundary words in body.
2. The last of the body should be ended with two - signs.

Answer 4

since version 2.0, the Request Body has an "Upload File..." link that allows you to post/upload binary data.