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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/TheArtOfHttpScripting | 94 |
1 files changed, 55 insertions, 39 deletions
diff --git a/docs/TheArtOfHttpScripting b/docs/TheArtOfHttpScripting index 183dd17a7..b0dab5ff2 100644 --- a/docs/TheArtOfHttpScripting +++ b/docs/TheArtOfHttpScripting @@ -1,5 +1,5 @@ Online: http://curl.haxx.se/docs/httpscripting.html -Date: May 28, 2008 +Date: Jan 19, 2011 The Art Of Scripting HTTP Requests Using Curl ============================================= @@ -38,10 +38,26 @@ Date: May 28, 2008 request a particular action, and then the server replies a few text lines before the actual requested content is sent to the client. - Using curl's option --verbose (-v as a short option) will display what kind of - commands curl sends to the server, as well as a few other informational texts. - --verbose is the single most useful option when it comes to debug or even - understand the curl<->server interaction. + The client, curl, sends a HTTP request. The request contains a method (like + GET, POST, HEAD etc), a number of request headers and sometimes a request + body. The HTTP server responds with a status line (indicating if things went + well), response headers and most often also a response body. The "body" part + is the plain data you requested, like the actual HTML or the image etc. + + 1.1 See the Protocol + + Using curl's option --verbose (-v as a short option) will display what kind + of commands curl sends to the server, as well as a few other informational + texts. + + --verbose is the single most useful option when it comes to debug or even + understand the curl<->server interaction. + + Sometimes even --verbose is not enough. Then --trace and --trace-ascii offer + even more details as they show EVERYTHING curl sends and receives. Use it + like this: + + curl --trace-ascii debugdump.txt http://www.example.com/ 2. URL @@ -61,10 +77,10 @@ Date: May 28, 2008 you get a web page returned in your terminal window. The entire HTML document that that URL holds. - All HTTP replies contain a set of headers that are normally hidden, use - curl's --include (-i) option to display them as well as the rest of the - document. You can also ask the remote server for ONLY the headers by using the - --head (-I) option (which will make curl issue a HEAD request). + All HTTP replies contain a set of response headers that are normally hidden, + use curl's --include (-i) option to display them as well as the rest of the + document. You can also ask the remote server for ONLY the headers by using + the --head (-I) option (which will make curl issue a HEAD request). 4. Forms @@ -127,7 +143,8 @@ Date: May 28, 2008 And to use curl to post this form with the same data filled in as before, we could do it like: - curl --data "birthyear=1905&press=%20OK%20" http://www.hotmail.com/when/junk.cgi + curl --data "birthyear=1905&press=%20OK%20" \ + http://www.example.com/when.cgi This kind of POST will use the Content-Type application/x-www-form-urlencoded and is the most widely used POST kind. @@ -204,7 +221,7 @@ Date: May 28, 2008 Put a file to a HTTP server with curl: - curl --upload-file uploadfile http://www.uploadhttp.com/receive.cgi + curl --upload-file uploadfile http://www.example.com/receive.cgi 6. HTTP Authentication @@ -217,7 +234,7 @@ Date: May 28, 2008 To tell curl to use a user and password for authentication: - curl --user name:password http://www.secrets.com + curl --user name:password http://www.example.com The site might require a different authentication method (check the headers returned by the server), and then --ntlm, --digest, --negotiate or even @@ -257,7 +274,7 @@ Date: May 28, 2008 Use curl to set the referer field with: - curl --referer http://curl.haxx.se http://daniel.haxx.se + curl --referer http://www.example.come http://www.example.com 8. User Agent @@ -273,13 +290,13 @@ Date: May 28, 2008 is time to set the User Agent field to fool the server into thinking you're one of those browsers. - To make curl look like Internet Explorer on a Windows 2000 box: + To make curl look like Internet Explorer 5 on a Windows 2000 box: - curl --user-agent "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)" [URL] + curl --user-agent "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)" [URL] - Or why not look like you're using Netscape 4.73 on a Linux (PIII) box: + Or why not look like you're using Netscape 4.73 on an old Linux box: - curl --user-agent "Mozilla/4.73 [en] (X11; U; Linux 2.2.15 i686)" [URL] + curl --user-agent "Mozilla/4.73 [en] (X11; U; Linux 2.2.15 i686)" [URL] 9. Redirects @@ -294,7 +311,7 @@ Date: May 28, 2008 To tell curl to follow a Location: - curl --location http://www.sitethatredirects.com + curl --location http://www.example.com If you use curl to POST to a site that immediately redirects you to another page, you can safely use --location (-L) and --data/--form together. Curl will @@ -321,13 +338,13 @@ Date: May 28, 2008 The simplest way to send a few cookies to the server when getting a page with curl is to add them on the command line like: - curl --cookie "name=Daniel" http://www.cookiesite.com + curl --cookie "name=Daniel" http://www.example.com Cookies are sent as common HTTP headers. This is practical as it allows curl to record cookies simply by recording headers. Record cookies with curl by using the --dump-header (-D) option like: - curl --dump-header headers_and_cookies http://www.cookiesite.com + curl --dump-header headers_and_cookies http://www.example.com (Take note that the --cookie-jar option described below is a better way to store cookies.) @@ -338,24 +355,25 @@ Date: May 28, 2008 believing you had a previous connection). To use previously stored cookies, you run curl like: - curl --cookie stored_cookies_in_file http://www.cookiesite.com + curl --cookie stored_cookies_in_file http://www.example.com Curl's "cookie engine" gets enabled when you use the --cookie option. If you only want curl to understand received cookies, use --cookie with a file that - doesn't exist. Example, if you want to let curl understand cookies from a page - and follow a location (and thus possibly send back cookies it received), you - can invoke it like: + doesn't exist. Example, if you want to let curl understand cookies from a + page and follow a location (and thus possibly send back cookies it received), + you can invoke it like: - curl --cookie nada --location http://www.cookiesite.com + curl --cookie nada --location http://www.example.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 --cookie (-b) switch automatically - detects if a given file is such a cookie file and parses it, and by using the - --cookie-jar (-c) option you'll make curl write a new cookie file at the end of - an operation: + between browsers and automatic scripts. The --cookie (-b) switch + automatically detects if a given file is such a cookie file and parses it, + and by using the --cookie-jar (-c) option you'll make curl write a new cookie + file at the end of an operation: - curl --cookie cookies.txt --cookie-jar newcookies.txt http://www.cookiesite.com + curl --cookie cookies.txt --cookie-jar newcookies.txt \ + http://www.example.com 11. HTTPS @@ -371,7 +389,7 @@ Date: May 28, 2008 Curl supports encrypted fetches thanks to the freely available OpenSSL libraries. To get a page from a HTTPS server, simply run curl like: - curl https://that.secure.server.com + curl https://secure.example.com 11.1 Certificates @@ -382,7 +400,7 @@ Date: May 28, 2008 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: - curl --cert mycert.pem https://that.secure.server.com + curl --cert mycert.pem https://secure.example.com curl also tries to verify that the server is who it claims to be, by verifying the server's certificate against a locally stored CA cert @@ -403,17 +421,18 @@ Date: May 28, 2008 For example, you can change the POST request to a PROPFIND and send the data as "Content-Type: text/xml" (instead of the default Content-Type) like this: - curl --data "<xml>" --header "Content-Type: text/xml" --request PROPFIND url.com + curl --data "<xml>" --header "Content-Type: text/xml" \ + --request PROPFIND url.com You can delete a default header by providing one without content. Like you can ruin the request by chopping off the Host: header: - curl --header "Host:" http://mysite.com + curl --header "Host:" http://www.example.com You can add headers the same way. Your server may want a "Destination:" header, and you can add it: - curl --header "Destination: http://moo.com/nowhere" http://url.com + curl --header "Destination: http://nowhere" http://example.com 13. Web Login @@ -444,7 +463,6 @@ Date: May 28, 2008 to do a proper login POST. Remember that the contents need to be URL encoded when sent in a normal POST. - 14. Debug Many times when you run curl on a site, you'll notice that the site doesn't @@ -480,12 +498,10 @@ Date: May 28, 2008 RFC 2616 is a must to read if you want in-depth understanding of the HTTP protocol. - RFC 2396 explains the URL syntax. + RFC 3986 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 |