Parse Request Data

parsed data source#

The data in a request contains the following parts:

• Router params: Refers to the obtained parameter list in routing path matching. For example: id in Router::with_path("/users/<id>/").
• URL queries: List of parameters to parse from the URL’s query string. For example 123 in http://localhost/user_id=123.
• Headers: The list of parameters in the request header.
• Form: A list of parameters to submit as POST.

This data can be parsed into strongly typed structures by providing several functions through Request.

• parse_params: parse the requested router params into a specific data type;
• parse_queries: parse the requested URL queries into a specific data type;
• parse_headers: parse the requested HTTP haders into a specific data type;
• parse_json: Parse the data in the HTTP body part of the request as JSON format to a specific type;
• parse_form: Parse the data in the HTTP body part of the request as a Form form to a specific type;
• parse_body: Parse the data in the HTTP body section to a specific type according to the type of the requested content-type.
• parse_data: can combine different data sources to parse a specific type, acceptable data sources are: router params, URL queries, HTTP haders, Form. To prevent unexpected errors, each data source cannot have the same key name. For example: http://localhost/users/<id>?id=123, <id> represents the id obtained by route matching, and there is also a id=123 in the URL queries part, in this case it cannot be Merged router params and URL queries to resolve to a specific type.

Parsing principle#

The customized serde::Deserializer will be pase data similar to HashMap<String, String> and HashMap<String, Vec<String>> into a specific data type.

For example: URL queries is actually parsed as a MultiMap type, MultiMap can think of it as a data structure like HashMap<String, Vec<String>>. If the requested URL is http://localhost/users?id=123&id=234, we provide The target type is:

#[derive(Deserialize)]
struct User {
  id: i64
}

Then the first id=123 will be parsed, and id=234 will be discarded:

let user: User = req.parse_queries().unwrap();
assert_eq!(user.id, 123);

If the type we provide is:

#[derive(Deserialize)]
struct Users {
  id: Vec<i64>
}

Then id=123&id=234 will be parsed:

let users: Users = req.parse_queries().unwrap();
assert_eq!(user.ids, vec![123, 234]);

Multiple data sources can be merged to parse out a specific type. The first is to define the data source:

use enumflags2::make_bitflags;

let source = make_bitflags!(ParseSource::{Queries|Form});

The data parts of URL queries and Form are combined here, and then call parse_data to parse. For specific examples, see: [parse-data](https:/ /github.com/salvo-rs/salvo/blob/main/examples/parse-data/src/main.rs).