Ruby and web development

1. Write CGI

A simple CGI program is as follows:

#! /Usr/bin/ENV Ruby
Print "HTTP/1.0 200 okrn"
Print "Content-Type: text/htmlrnrn"
Print "Hello world! RN"

We can use Ruby to process submitted parameters, fill templates, generate HTML, and so on, but it is a little troublesome. We can use the CGI Module.

2. Use CGI. Rb

CGI. Rb is used to write CGI scripts. It can operate form, cookies, environment variables, and maintain sessions. You should know where to find the specific usage.

3. Reference and escape

/The URL contains a special character, including <and>, and sometimes needs to be escaped (escaped), for example,/is converted to % 2f. CGI. RB provides two functions: CGI. Escape and CGI. Unescape:

Require 'cgi'
Puts CGI. Escape ("Nicolas Payton/trumpet & flugel horn ")

Result:

Nicholas + Payton % 2 ftrumpet + % 26 + flugel + Horn

Example of escaping elements in HTML documents (Omitted ):

4. Form

CGI-like can be used to obtain the data submitted by the client in two ways. Joined the user to submit lookup? Player = Tom & year = 1958, which can be accessed directly using the CGI [] array.

Require 'cgi'
CGI = CGI. New
CGI ['player'] #-> ["Tom"]
CGI ['Year'] #-> ["1958"]

Another way is to use a hash table to obtain all parameters and values.

Require 'cgi'
CGI = CGI. New
H = CGI. Params
H ['player'] #-> ["Tom"]

5. Generate form and HTML

CGI class provides a lot of methods for generating HTML, almost every tag is a method. The example is more intuitive:

Require "cgi"
CGI = CGI. New ("html3") # Add HTML generation methods
CGI. out {
Cgi.html {
CGI. head {"N" + CGI. Title {"this is a test" }}+
CGI. Body {"N" +
CGI. FORM {"N" +
CGI. HR +
CGI. H1 {"a form:"} + "N" +
CGI. textarea ("get_text") + "N" +
Cgi.br +
CGI. Submit
}
}
}
}

Generate the following code:

6. Cookies

Require "cgi"
Cookie = CGI: Cookie. New ("rubyweb", "custid = 123", "part = ABC ");
CGI = CGI. New ("html3 ")
CGI. Out ("cookie" => [cookie]) {
Cgi.html {
"Nhtml content here"
}
}

The generated header is as follows:

Content-Type: text/html
Content-Length: 86
Set-COOKIE: rubyweb = custid % 3d123 & Part % 3 dabc; Path =

Then, when you access the page again, you can read this value.

Require "cgi"
CGI = CGI. New ("html3 ")
CGI. out {
Cgi.html {
CGI. Pre {
Cookie = CGI. Cookies ["rubyweb"]
"Ncookies aren" + Cookie. value. Join ("N ")
}
}

7. Sessions

To process a session, an additional class is required: CGI: Session.

Require "cgi"
Require "cgi/session"

CGI = CGI. New ("html3 ")
Sess = CGI: Session. New (CGI, "session_key" => "rubyweb ",
"Session_id" = & gt; "9650 ",
"New_session" => true,
"Prefix" => "Web-session .")
Sess [& quot; custid & quot;] = 123
Sess ["part"] = "ABC"

CGI. out {
Cgi.html {
"Nhtml content here"
}
}

Read the session using the following code:

Require "cgi"
Require "cgi/session"

CGI = CGI. New ("html3 ")
Sess = CGI: Session. New (CGI, "session_key" => "rubyweb ",
"Prefix" => "Web-session .")
CGI. out {
Cgi.html {
"Ncustomer # {sess ['lastid']} orders an # {sess ['part']}"
}
}