Chapter 5. Publishing Procedures
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Chapter 5. Publishing Procedures

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Publishing Procedures

Procedures can be published to virtual paths of an application server within the hierarchy of a siscweb application. Publishing can be done both interactively at the server-side REPL during development, and in the web.xml file at deployment time. (See the section called “The Adapter Servlet”.)

Publishing Procedures

Requires: (import siscweb/publish)
Located in: siscweb.jar

This module provides simple procedures to publish procedures to URL patterns. Patterns can be expressed either as wildcards or regular expressions.

Published procedures accept a single parameter in the form of a request object.

Warning

Since the Java HttpServletRequest object is not serializable, it is a good practice to clear any reference to it as soon as possible.

Wildcard patterns can use wildcards and double-wildcards between slashes, such as in "/hello/*" or "/hello/**/world". The first pattern matches requests such as "/hello/there", "/hello/", or even "/hello"; the second pattern matches "/hello/world" as well as "hello/what/a/wonderful/world/".

procedure: (publish/wildcard url-wildcard-pattern (lambda (request) ...)) => undefined
procedure: (publish/wildcard url-wildcard-pattern symbol) => undefined

Publishes the given procedure proc or symbol at url-wildcard-pattern. The symbol will be looked up at run time every time. This is especially useful during development, since it allows one to redefine the procedure associated to symbol without having to republish.

When a request is received, the path-info section of the request URL is matched against each published pattern. If a match is found, the corresponding procedure is invoked. The procedure will receive the HTTP request as its only argument. 

          
(publish/wildcard
  "/hello-world/*"
  (lambda (request)
    (set! request #f)
    (send-html/back
    `(html
      (head (title "Hello, world!"))
      (body (p "Hello, world!"))))))

procedure: (publish/regexp url-regexp-pattern (lambda (request) ...)) => undefined
procedure: (publish/regexp url-regexp-pattern symbol) => undefined

This function is equivalent to publish/wildcard, save for the fact that it accepts a regular expression as a pattern.

procedure: (publish url-wildcard-pattern (lambda (request) ...)) => undefined
procedure: (publish url-wildcard-pattern symbol) => undefined

This function is equivalent to publish/wildcard, and is present both for backwards compatibility and to offer a convenient shorthand.

procedure: (unpublish url-pattern) => undefined

Removes a previously published procedure at the given pattern. The url-pattern passed to unpublish must be identical to the one used to publish.

procedure: (get-published url-pattern) => procedure/#f

Returns the procedure published at the given url-pattern or #f if none is found.

procedure: (get-all-published) => alist

Returns an association list made of (pattern procedure notation) elements or '() if no procedures are published.

procedure: (publish-bulk ((url-pattern [procedure|symbol] notation) ...)) => undefined

Given an association list of (url-pattern procedure notation), publishes all the given procedures or symbols to the provided patterns.

Depending on whether notation is the symbol 'wildcard or 'regexp, the given url-pattern should be either a wildcard or regular expression pattern.

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Chapter 4. Managing Program State Home Chapter 6. Request Bindings