Processing Flow

Service first converts the request into salvo's Response, and then enters the route matching stage.

Route matching phase

Route matching runs filters in the order of addition, from outside to inside and from top to bottom. If any filter fails to execute, it will be considered a match failure.

During the matching process, there is path information to be given to the request. As the matching proceeds, once the path filter successfully matches, it will consume the path it matches. When all paths are consumed and no filter fails to match on the matching link, the last Router on the current link has a goal Handler, then the match is successful, the matching phase ends, and the Handler on all matching links is collected and matched to enter the execution phase.

If the path is not consumed, the filter on the link does not report an error, but there are no more sub-routes to continue matching, then the current link is considered to have failed to match, and the next route matching will be entered.

If all routes are matched and there is no success, then the error capture phase will be entered.

Handler execution phase

Execute Handler in sequence according to the Handler list collected in the matching phase. During the execution process, the previous middleware can call ctrl::call_next() Let the subsequent middleware execute first, and then execute your own logic. If there is a status code error or redirection during the execution, the subsequent Handler will no longer be executed. At this time, if the status code is an error, and the Body of the Response is not set or is ResBody::Error, it will enter the error capture phase, otherwise it will skip the capture phase.

Error capture phase

Catcher is a type used to handle errors. It can also add middleware (hoops). The error will pass through all Handler in Catcher in turn. If a Handler has handled the error and you don't want the subsequent Handler to continue executing, you can skip the subsequent Handler through ctrl.skip_rest() and end the capture phase directly.

Catcher must contain a Handler by default for default error handling. The default is DeaultGoal, and you can also completely customize your own Handler as the default implementation of error handling. It will be based on the content-type required by the request header Displays error messages in the corresponding format, supporting four display formats: json, xml, text, and html. DeaultGoal also provides some display settings. For example, by default it will display salvo related links when displaying html format. You can call DefaultGoal::footer or DefaultGoal::with_footer to set it to your desired custom footer.

Service will convert salvo's Response to hyper's Response type, and finally return it to the browser and other clients.