Curl Header Information

Tag: http , curl Author: whoissun Date: 2013-10-05

I am trying to upload data to a webserver using curl. I have analyzed the data sent to the server, from a browser, using wireshark, shown below:

POST /cgi-bin/upload.cgi HTTP/1.1
Connection: keep-alive
Content-Length: 2637
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) 
Chrome/30.0.1599.101 Safari/537.36
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryn1sckmiVOVfCwUMQ
Accept-Encoding: gzip,deflate,sdch
Accept-Language: en-US,en;q=0.8

I looked at the webpage the browser accesses to upload the information, shown below:

<form method="POST" enctype="multipart/form-data" action="">
File to upload: 
<input type="file" name="theupload"><br>
Should it be updated?<input type="checkbox" name="configuration"><br>
<input type="submit" value="Press"> to upload the file!

I attempted to use:

curl --referer -F [email protected] -F config=on

My output was

POST /cgi-bin/upload.cgi HTTP/1.1
User-Agent: curl/7.33.0
Accept: */*
Content-Length: 2650
Expect: 100-continue
Content-Type: multipart/form-data; boundary=------------------------fd126312049d1f47

The server returns HTTP/1.1 417 Expectation Failed. I am just learning curl, and I am unsure of what to do. Do i need to emulate the header of the browser command as closely as possible? or is the boundary what is probably throwing it off? Thanks for you help.

Best Answer

try to use curl -H "Expect:" ...


It worked, great. Thanks. Why would the "Expects" string default?
@user2558056 curl uses 14.20 Expect header by default as it is http 1.1 client and before sending body ask server "do you accept it?", web server or proxy in your case do not understand this behaviour