SQLPage documentation
The two most important concepts in SQLPage are components and parameters. This page documents all the components that you can use in SQLPage and their parameters. Use this as a reference when building your SQL application.
components
The "http_header" component
An advanced component that can be used to create redirections, set a custom caching policy to your pages, or set any HTTP header. If you are a beginner, you probably don't need this component. When used, this component has to be the first component in the page, because once the page is sent to the browser, it is too late to change the headers. Any valid HTTP header can be used as a top-level parameter for this component. HTTP headers are additional pieces of information sent with responses to web requests that provide instructions or metadata about the data being sent — for example, setting cache control directives to control caching behavior or specifying the content type of a response.
Top-level parameters
Access-Control-Allow-Origin
Specifies which origins are allowed to access the resource in a cross-origin request, used for implementing Cross-Origin Resource Sharing (CORS).
Cache-Control
Directives for how long the page should be cached by the browser. Set this to max-age=N to keep the page in cache for N seconds.
Content-Disposition
Provides instructions on how the response content should be displayed or handled by the client, such as inline or as an attachment.
Location
Specifies the URL to redirect the client to, usually used in 3xx redirection responses.
Set-Cookie
Sets a cookie in the client browser, used for session management and storing user-related information.
Example 1
Set cache control directives for caching behavior. In this example, the response can be cached by the browser and served from the cache for up to 600 seconds (10 minutes) after it is first requested. During that time, even if the cached response becomes stale (outdated), the browser can still use it (stale-while-revalidate) for up to 3600 seconds (1 hour) while it retrieves a fresh copy from the server in the background. If there is an error while trying to retrieve a fresh copy from the server, the browser can continue to serve the stale response for up to 86400 seconds (24 hours) (stale-if-error) instead of showing an error page. This caching behavior helps improve the performance and responsiveness of the website by reducing the number of requests made to the server and allowing the browser to serve content from its cache when appropriate.
SELECT
'http_header' as component,
'public, max-age=600, stale-while-revalidate=3600, stale-if-error=86400' as Cache-Control;
Example 2
Redirect the user to another page. In this example, the user is redirected to a file named another-page.sql at the root of the website. The current page will not be displayed at all. This is useful in particular for content creation pages that contain only INSERT statements, because you can redirect the user to the page that lists the content after it has been created.
SELECT
'http_header' as component,
'/another-page.sql' as Location;