Portal Servlets
This section discusses:
Portal servlets.
Page assembly for page-based templates.
A portal servlet is a Java servlet that runs on the portal web server. It intercepts a user request for an HTML page, retrieves the requested page, envelopes the page with additional content, and then sends the resulting page to the user’s browser. It enables the portal to integrate content from a wide variety of sources and present the content on a single page in a coherent, consistent fashion.
The portal servlet performs these functions:
Retrieves user-requested content.
The content can be either target content, such as a PeopleSoft application page, for display in the large target region of the browser, or content for the smaller-sized pagelets.
Note: Portal servlets do not accept HTTP PUT requests from clients. They accept only HTTP GET or POST data from clients. If the portal servlet is sent a PUT request, a 405 error page appears.
See World Wide Web Consortium, Hypertext Transfer Protocol — HTTP/1.1.
Provides a consistent user interface.
The portal servlet checks properties associated with each content reference, including the name of a portal template. When a user accesses content through the portal, the portal servlet wraps the target page with the portal template specified in the content reference. This template provides a consistent user interface.
Ensures that PeopleSoft-specific tags are processed correctly.
Developers create portal pages using a template-based layout system. In addition to traditional HTML tags, templates can contain PeopleSoft-specific tags that a normal browser cannot interpret. The portal servlet can interpret these PeopleSoft-specific tags when constructing templates, and can interpret any other HTML content, at runtime. The portal servlet then sends the resulting page to a browser as a single HTML document.
The portal servlet's behavior changes slightly depending on whether it's handling page-based or frame-based templates.
Page-Based Template Handling
For page-based templates, the portal servlet assembles pages for the browser and ensures that all URL references in the HTML on the assembled pages are referenced back to the portal servlet itself.
The portal servlet receives user requests for content and then constructs a single, complete HTML page for the user’s browser by combining the requested content with the appropriate portal template. This process is called page assembly. The portal servlet uses a template to incorporate the contents of the requested page into the context of the site (headers, navigation, and so on). Each content reference can be associated with a template in the portal registry. The template tells the portal servlet what URLs to combine and how to arrange them in the user’s browser.
Note: The portal servlet uses relative URLs. The portal servlet performs URL rewriting (serves as a proxy) only when the URL is generated by an external system or a PeopleTools release prior to 8.4.
Pages that the portal servlet assembles for the browser might point to numerous other web pages from different sources on the internet. Because the user’s request goes through the portal servlet, the servlet must ensure that requests for content can be fulfilled during the page assembly process. In some cases, each URL in the HTML document assembled by the portal servlet must be rewritten to reference the portal servlet, not the originally requested URL. This process of redirecting URLs so that they point to the portal servlet is called proxying. Nevertheless, the portal servlet does not function as a reverse proxy server.
Frame-Based Template Handling
For a frame-based template, the portal servlet updates the src tags in the frameset with the target content before sending the page to the browser.
The portal servlet inserts a URL into each frame in the src tag and sends the page to the browser, rather than retrieving documents for the browser, as it does with page-based templates.
iFrame-Based Template Handling
For an iframe-based template, the portal servlet updates the src tags for each inline frame (iframe) element in the document with the target content before sending the page to the browser. The portal servlet inserts a URL into each frame in the src tag and sends the page along to the browser, rather than retrieving documents for the browser, as it does with page-based templates.
Portal Servlet Setup
A portal servlet must be set up properly on a web server before the portal can service user requests. The web server and portal servlet environment should be configured and tested during the installation of PeopleSoft applications.
See PeopleSoft 9.2 Application Installation for your database platform.
When a user clicks a link on a page-based template, the portal servlet receives the user’s request, retrieves the content, properly formats it using a predefined portal template, and sends the assembled page back to the user’s browser. The portal servlet also ensures that the user has the proper security permissions and is allowed to view the page.
The following processing steps occur during the page-assembly process:
The browser sends a request for content to the portal web server.
The browser sends an HTTP request for target content; the request includes the target URL. The portal web server invokes the portal servlet. If the request includes a URL from a PeopleTools release prior to 8.4, the portal servlet then identifies the target content based on the query string parameter that was inserted there when the referring page was proxied.
The portal servlet checks the portal registry to determine whether a content reference exists for the target URL.
If a content reference exists for the target URL and the user does not have access to the content reference, the portal servlet responds with an error message. If the user does have access, the portal servlet continues its processing. If the content reference has been registered with a frame template, the portal servlet constructs the template and returns it as the response to the browser. The browser gets the content for each frame in the usual way. If the content reference has been registered as having no template, the servlet sends a redirect response to the browser for the original content. Otherwise, it goes on to the next step.
The portal servlet retrieves the appropriate template.
If a registered content reference was found in the previous step, then the template associated with that content reference is used to wrap that content. If no template is associated, the portal servlet uses the template for the node associated with the content reference. If no node is associated with the content reference, then the default template for the portal is used. If no default portal template exists, the content appears without any template.
The portal servlet issues HTTP requests for content.
The portal servlet issues an HTTP request for the requested content to the appropriate web server and receives an HTML document in return. It also issues an HTTP request for each pagelet used in the template.
The portal servlet merges content from previous versions of PeopleTools 8.4 from all HTML documents that it retrieved into the template HTML, and sends a single, complete HTML document back to the user’s browser.
The template HTML may contain special PeopleSoft tags, including the Target tag and the Pagelet tag. Each Target tag is replaced with whatever content is retrieved when the request for target content is fulfilled. Each Pagelet tag is replaced with the proxied content specified by that tag.
If a style sheet is associated with the template, it is used. If not, the style sheet associated with the target content is used. Style sheets included in template pagelets are used if they are present. Additionally, the portal servlet ensures that cookies and headers returned in the responses for the template pagelets are merged into the main response.