added some -c talk, spell checked

Online:  http://curl.haxx.se/docs/httpscripting.shtml

Author:  Daniel Stenberg <daniel@haxx.se>

Date:    August 20, 2001

Version: 0.4

Date:    October 31, 2001

Version: 0.5

                The Art Of Scripting HTTP Requests Using Curl

                =============================================

2. URL

 The Uniform Resource Locator format is how you specify the address of a

 particular resource on the internet. You know these, you've seen URLs like

 particular resource on the Internet. You know these, you've seen URLs like

 http://curl.haxx.se or https://yourbank.com a million times.

3. GET a page

 The simplest and most common request/operation made using HTTP is to get a

 URL. The URL could itself refer to a web page, an image or a file. The client

 issues a GET request to the server and receives the document it asked for.

 If you isse the command line

 If you issue the command line

        curl http://curl.haxx.se

          <input type=submit name=press value="OK">

        </form>

  In your favourite browser, this form will appear with a text box to fill in

  In your favorite browser, this form will appear with a text box to fill in

  and a press-button labeled "OK". If you fill in '1905' and press the OK

  button, your browser will then create a new URL to get for you. The URL will

  get "junk.cgi?birthyear=1905&press=OK" appended to the path part of the

 4.3 FILE UPLOAD POST

  Back in late 1995 they defined a new way to post data over HTTP. It was

  documented in the RFC 1867, why this method sometimes is refered to as

  a rfc1867-posting.

  documented in the RFC 1867, why this method sometimes is referred to as

  a RFC1867-posting.

  This method is mainly designed to better support file uploads. A form that

  allows a user to upload a file could be written like this in HTML:

  way your browser does.

  An easy way to get to see this, is to save the HTML page with the form on

  your local disk, mofidy the 'method' to a GET, and press the submit button

  your local disk, modify the 'method' to a GET, and press the submit button

  (you could also change the action URL if you want to).

  You will then clearly see the data get appended to the URL, separated with a

 Sometimes your HTTP access is only available through the use of a HTTP

 proxy. This seems to be especially common at various companies. A HTTP proxy

 may require its own user and password to allow the client to get through to

 the internet. To specify those with curl, run something like:

 the Internet. To specify those with curl, run something like:

        curl -U proxyuser:proxypassword curl.haxx.se

 contents to the server, unless of course they are expired.

 Many applications and servers use this method to connect a series of requests

 into a single logical session. To be able to use curl in such occations, we

 into a single logical session. To be able to use curl in such occasions, we

 must be able to record and send back cookies the way the web application

 expects them. The same way browsers deal with them.

        curl -b nada -L www.cookiesite.com

 Curl has the ability to read and write cookie files that use the same file

 format that Netscape and Mozilla do. It is a convenient way to share cookies

 between browsers and automatic scripts. The -b switch automatically detects

 if a given file is such a cookie file and parses it, and by using the

 -c/--cookie-jar option you'll make curl write a new cookie file at the end of

 an operation:

        curl -b cookies.txt -c newcookies.txt www.cookiesite.com

11. HTTPS

 There are a few ways to do secure HTTP transfers. The by far most common

  you need to enter the unlock-code before the certificate can be used by

  curl. The PIN-code can be specified on the command line or if not, entered

  interactively when curl queries for it. Use a certificate with curl on a

  https server like:

  HTTPS server like:

        curl -E mycert.pem https://that.secure.server.com

 RFC 2616 is a must to read if you want in-depth understanding of the HTTP

 protocol.

 RFC 2396 explains the URL syntax

 RFC 2396 explains the URL syntax.

 RFC 2109 defines how cookies are supposed to work.

 RFC 1867 defines the HTTP post upload format.

 http://www.openssl.org is the home of the OpenSSL project

 http://curl.haxx.se is the home of the cURL project