Web Server Reference

PxPlus Web Server Variables

 

The PxPlus Web Server gives you access in your programs to some of its own variables. These variables are created or filled by the Web Server and/or with information received from the browser. A leading % (percent sign) indicates that the variable is global.

Web Server Variable

Value(s)

Warning

The following variables are reserved for exclusive use by the PxPlus Web Server for special file channel values.

Important Note:
DO NOT use these file channels:
 
   %mime
   %tmpl 
   %hits
   %serv 
   %TCP_FN

You can use %body_buff in your applications but for READing only. See %body_buff below.

%allow$

Allowed methods recognized by the browser.

%args$[%args]

The %args$[ ] array contains the command line arguments passed to the task handler by the URL request, with %args (number of arguments passed) ranging from 1 to the total number of arguments passed.

%authorization$

USERID/PASSWORD screen if passed from the browser. Typically encoded in Base64.

%body_buff

The Web Server uses this file channel for an incoming request's body. It converts the first 32000 bytes into variables and ignores the rest, but leaves all of the body in %body_buff so that it is available if you need it. This is a *memory* file with a maximum record size of 8192 bytes. Data is blocked into more than one data record (beginning IND=0 to IND=n).

You can use %body_buff in your applications, but it should only be READ from. The file whose channel is in the numeric variable %body_buff contains any body information sent in a POST request. If your POST sends more information than will fit in a single PxPlus STRING variable, then you must retrieve it manually from the %body_buff channel.

Note:
%content_type$ will tell you the mime type of the body content. %content_length will tell you the body's total length (number of bytes).

Example:

   READ RECORD(%BODY_BUFF,IND=0)A$ !Reads first block

   READ RECORD(%BODY_BUFF,END=DONE) !Reads remaining blocks

%cgi$

Contains a compiled IOLIST of all the variable names passed.

%content_encoding$

Data encoding if the browser pre-encodes the data.

%content_filename$

If you set this to a file name (no path), the Web Server adds a Content-Disposition header to the outgoing data stream. This notifies the browser to "Save As" the file name you supply.

Note:
You can use this to send a PxPlus program to a browser without running it. (A typical link to a browser page would RUN a PxPlus program if clicked on.)

%content_length

Length of the content received. This variable will contain the length of the response if it is provided by the browser. You do not need to set this when your PxPlus application finishes. The task handler will calculate it, based on the data output and any automatic translation done to send your data back.

%content_type$

Content or mime type. If the browser sends a content type, the value is available to your PxPlus program. If your PxPlus application does not assign a %content_type$, the Web Server defaults to text/html.

If your PxPlus application overrides the default %content_type$, then the Web Server will pass your value for the content type back to the browser. If the %content_type$ begins with "text/", then the Web Server automatically performs any required end-of-line conversions.

%cookie.rcv

Number of cookies received from the browser.

%cookie.snd

Number of cookies you SET and send to the browser. The cookies are stored in strings of %cookie.n$, where n is the cookie number.

%document_label$

The line label entry point for your program, if given in the URL; e.g. myprog;entry.

%document_root$

The Root directory for the request.

%document_uri$

The file name portion after the protocol and server in the URL request.

Note:
uri is an acronym for Uniform Resource Indicator.

%exit_code

Error status on exit. The task handler will set %exit_code to an appropriate value. The value is typically 200 ("OK") unless there is a problem (such as in situations where the task prematurely disconnects, or there is no data output).

Valid codes include:

   200 - OK
   201 - Created
   202 - Accepted
   204 - No Content
   300 - Multiple Choices
   301 - Moved Permanently
   302 - Moved Temporarily
   304 - Not Modified
   307 - Temporary Redirect
   400 - Bad Request
   401 - Unauthorized
   403 - Forbidden
   404 - Not Found
   500 - Internal Server Error
   501 - Not Implemented
   502 - Bad Gateway
   503 - Service Unavailable

The Web Server returns an Error 403 Forbidden on browser requests for PxPlus data files (i.e. keyed, indexed).

You can assign a value to %exit_code if you want to force the task handler to return a specific error code. For example, if you set %exit_code=401, the task handler will return an Error 401 to the browser.

%exit_include_html

Setting this variable, along with setting %exit_code, tells the Web Server that the output that has been output to %print_fn should be returned to the browser instead of the generic error message page. This is often used to return additional error information or JSON data providing details of the problem.

(The %exit_include_html variable was added in PxPlus 2021.)

%from$

Source, if the browser sends a From.

%hit_counter

Current number of hits for your page, if any.

html_file $

Name of the HTML page you want *web/merge to evaluate and dynamically send to the %print_fn channel.

%http_accept$

Mime content types the browser will accept from you. */* means any content type.

%http_accept_encoding$

Any inline encoding or compression methods the browser has available for your use.

%http_accept_language$

Language that the browser wants you to send in.

%http_cookie$

The string of cookies received from the browser.

%http_extraheaders

This variable can be loaded by the application with additional HTTP headers to be returned with the Web page. Each header should be separated by $0A$ or the SEP character.

(The %http_extraheaders variable was added in PxPlus v11.00.)

%http_referer$

Referral source, if the browser was pointed to your website by some other location. The name of the URL that originated the request.

%http_user_agent$

Details about the browser type connecting to you.

%ismas90

Value is 1 if using the Web Server inside Mas90's internet access module; otherwise, value is 0 (zero).

%lang$

The LANG file extension in use in PxPlus. (Default is .en.)

%new_location$

This is an internal variable set during a redirection request. It should be used only when the user's browser should go to another page automatically.

When a browser makes a request for a URL, you can force the browser to "go somewhere else" or make another request for something else by setting %new_location to the URL you actually want the browser to request and by setting your %exit_code=301 (see %exit_code). You must set both these values to force a browser to automatically generate a new request for the URL in %new_location$.

%path_translated$

The Root directory plus the file name portion of the URL requested, with delimiters based on the O/S on which the Web Server is currently running (the \ backslash for Windows or the standard / forward slash for UNIX).

%print_fn

The setting for the file channel that the Web Server uses as a standard output channel.

In effect, the Web Server sets up a memory-resident logical file on the %print_fn channel. You dump your data into this file by using PRINT, WRITE and other output directives with %print_fn as the file channel and the Web Server transmits the contents for you (i.e. PRINT (%print_fn)data). The task handler will read the data in this example when your application is complete and send it back to the port monitor for transmission to the browser.

Note:
Your PxPlus web application should use ONLY this as the file channel for data that is sent to the browser.

%query_string$

The string of arguments following the file name in the URL.

%raw_next$

If set, %raw_next will add a NEXT button to the bottom of your %print_fn data if %raw_text=1. (%raw_text$ should be set to the URL to which you wish the button to jump.)

%raw_next_lbl$

The text to appear on your "next" button. (Default is the word "next".)

%raw_text

   0 = Output to the browser as is.
   1 = Wrap HTML header/body around output from the PxPlus application.

%raw_title$

If %raw_text is set, then %raw_title$ will be the title used in the HTML generated around your %print_fn output.

%remote_ip$

IP address (or DNS name) of the browser.

%request_method$

HTTP request method (set to GET, HEAD or POST).

%server_name$

Name of your host, as supplied by the browser connecting to you; e.g. www.pvxplus.com.

%server_port

TCP socket number that the web server is monitoring.

%server_protocol$

Set to HTTP/1.0.

%server_rootdir$

Default Root directory for the given server.

%server_software$

Name of the Web Server and version.

%smtp_gateway$

SMTP gateway you selected in your SMTP dialogue.

%smtp_socket

SMTP socket number you specified in your SMTP dialogue, prefixed by a ; (semi-colon). (Default is ;25.)

%tcp_fn

File channel that the task handler is using to talk to the port monitor.

Warning!
DO NOT perform any I/O on the %tcp_fn channel.

%time_offset

The offset to GMT time; e.g. =-500 (-5 hrs.) or =430 (+4 hrs. 30 minutes).

 

Note:
When you create PxPlus applications to service web requests, the Web Server automatically CLOSEs any and all file channels upon completing your PxPlus program task, except for: (a) any files belonging to the Web Server itself, and (b) any files which were open when the Web Server launched (any files you OPENed in your START_UP).

Regular variables are destroyed automatically when your application exits.

Clear any GLOBAL variables you create in your application. Since the Web Server works by multiple-task handling, the values will not be available between tasks and therefore are useless as a method of passing information from page to page. (Use cookies to pass information from one request to another.) DO NOT issue a START command.