Request handlers

Request handlers (from the module vinegar.request_handlers) are responsible for handling requests received by servers.

While custom request handlers can be implemented by providing a module with a get_instance_http or get_instance_tftp function that returns an instance of HttpRequestHandler or TftpRequestHandler respectively.

Warning

When implementing a custom request handler, be aware that the servers do not decode or sanitize the request path. Each request handler is responsible for URL decoding the request path and ensuring that it is not vulnerable to directory traversal attacks or other similar attacks.

Two different request handlers are bundled with Vinegar:

The file request handler serves resources from the file system. This can either be a single file or a whole directory of files. Files may be served as is, or they may be rendered as templates. When rendering files as templates, the request path can contain a system ID or another mean of identifying a specific system. In this case, the data (as provided by the data sources) for this system is made available to the template through the data context variable and the system’s system ID is made available through the id context variable.

Any template engine that can be instantiated through get_template_engine can be used with the file request handler. Please refer to the API reference for vinegar.request_handler.file for a full list of configuration options.

The other request handler is the sqlite_update request handler. This request handler has a very specific purpose: It can be used to update an SQLite database that is used by the sqlite data source. This means that it provides a way of dynamically updating the data associated with a system, possible from the installer environment.

Please refer to the API reference for vinegar.request_handler.sqlite_update to learn more about how this request handler can be configured to apply the desired changes.

In the next section we are going to learn more about how we can leverage the power of templates in Vinegar.