FAQ 9.1 What is the correct form of response from a CGI script?
in [Perl]
|
Prev: Perl in the workplace
Next: How to use Regex to breakdown a pattern and use the pattern to break down a string
From: PerlFAQ Server on 25 Jun 2010 12:00 This is an excerpt from the latest version perlfaq9.pod, which comes with the standard Perl distribution. These postings aim to reduce the number of repeated questions as well as allow the community to review and update the answers. The latest version of the complete perlfaq is at http://faq.perl.org . -------------------------------------------------------------------- 9.1: What is the correct form of response from a CGI script? (Alan Flavell <flavell+www(a)a5.ph.gla.ac.uk> answers...) The Common Gateway Interface (CGI) specifies a software interface between a program ("CGI script") and a web server (HTTPD). It is not specific to Perl, and has its own FAQs and tutorials, and usenet group, comp.infosystems.www.authoring.cgi The CGI specification is outlined in an informational RFC: http://www.ietf.org/rfc/rfc3875 Other relevant documentation listed in: http://www.perl.org/CGI_MetaFAQ.html These Perl FAQs very selectively cover some CGI issues. However, Perl programmers are strongly advised to use the "CGI.pm" module, to take care of the details for them. The similarity between CGI response headers (defined in the CGI specification) and HTTP response headers (defined in the HTTP specification, RFC2616) is intentional, but can sometimes be confusing. The CGI specification defines two kinds of script: the "Parsed Header" script, and the "Non Parsed Header" (NPH) script. Check your server documentation to see what it supports. "Parsed Header" scripts are simpler in various respects. The CGI specification allows any of the usual newline representations in the CGI response (it's the server's job to create an accurate HTTP response based on it). So "\n" written in text mode is technically correct, and recommended. NPH scripts are more tricky: they must put out a complete and accurate set of HTTP transaction response headers; the HTTP specification calls for records to be terminated with carriage-return and line-feed, i.e ASCII \015\012 written in binary mode. Using "CGI.pm" gives excellent platform independence, including EBCDIC systems. "CGI.pm" selects an appropriate newline representation ($CGI::CRLF) and sets binmode as appropriate. -------------------------------------------------------------------- The perlfaq-workers, a group of volunteers, maintain the perlfaq. They are not necessarily experts in every domain where Perl might show up, so please include as much information as possible and relevant in any corrections. The perlfaq-workers also don't have access to every operating system or platform, so please include relevant details for corrections to examples that do not work on particular platforms. Working code is greatly appreciated. If you'd like to help maintain the perlfaq, see the details in perlfaq.pod. |