[]Trait rocket::http::uri::FromUriParam

pub trait FromUriParam<P, T> where
    P: UriPart
{ type Target: UriDisplay<P>; fn from_uri_param(param: T) -> Self::Target; }

Conversion trait for parameters used in uri! invocations.

Overview

In addition to implementing UriDisplay, to use a custom type in a uri! expression, the FromUriParam trait must be implemented. The UriDisplay derive automatically generates identity implementations of FromUriParam, so in the majority of cases, as with UriDisplay, this trait is never implemented manually.

In the rare case that UriDisplay is implemented manually, this trait, too, must be implemented explicitly. In the majority of cases, implementation can be automated. Rocket provides the impl_from_uri_param_identity macro to generate the identity implementations automatically. For a type T, these are:

See impl_from_uri_param_identity for usage details.

Code Generation

This trait is invoked once per expression passed into a uri! invocation. In particular, for a route URI parameter of type T and a user-supplied expression of type S, <T as FromUriParam<S>>::from_uri_param is invoked. The returned value is used in place of the user's value and rendered using its UriDisplay implementation.

This trait allows types that differ from the route URI parameter's types to be used in their place at no cost. For instance, the following implementation, provided by Rocket, allows an &str to be used in a uri! invocation for route URI parameters declared as String:

impl<'a, P: UriPart> FromUriParam<P, &'a str> for String {
    type Target = &'a str;
}

Because the FromUriParam::Target type is the same as the input type, the conversion is a no-op and free of cost, allowing an &str to be used in place of a String without penalty. A similar no-op conversion exists for &RawStr:

impl<'a, 'b, P: UriPart> FromUriParam<P, &'a str> for &'b RawStr {
    type Target = &'a str;
}

Provided Implementations

The following types have identity implementations:

The following conversions are implemented, allowing a value of the type on the left to be used when a type on the right is expected by a route:

The following types have identity implementations only in Path:

The following conversions are implemented only in Path:

See Foreign Impls for all provided implementations.

Implementing

This trait should only be implemented when you'd like to allow a type different from the route's declared type to be used in its place in a uri! invocation. For instance, if the route has a type of T and you'd like to use a type of S in a uri! invocation, you'd implement FromUriParam<P, T> for S where P is Path for conversions valid in the path part of a URI, Uri for conversions valid in the query part of a URI, or P: UriPart when a conversion is valid in either case.

This is typically only warranted for owned-value types with corresponding reference types: String and &str, for instance. In this case, it's desirable to allow an &str to be used in place of a String.

When implementing FromUriParam, be aware that Rocket will use the UriDisplay implementation of FromUriParam::Target, not of the source type. Incorrect implementations can result in creating unsafe URIs.

Example

The following example implements FromUriParam<Query, (&str, &str)> for a User type. The implementation allows an (&str, &str) type to be used in a uri! invocation where a User type is expected in the query part of the URI.

use std::fmt;

use rocket::http::RawStr;
use rocket::http::uri::{Formatter, UriDisplay, FromUriParam, Query};

#[derive(FromForm)]
struct User<'a> {
    name: &'a RawStr,
    nickname: String,
}

impl<'a> UriDisplay<Query> for User<'a> {
    fn fmt(&self, f: &mut Formatter<Query>) -> fmt::Result {
        f.write_named_value("name", &self.name)?;
        f.write_named_value("nickname", &self.nickname)
    }
}

impl<'a, 'b> FromUriParam<Query, (&'a str, &'b str)> for User<'a> {
    type Target = User<'a>;

    fn from_uri_param((name, nickname): (&'a str, &'b str)) -> User<'a> {
        User { name: name.into(), nickname: nickname.to_string() }
    }
}

With these implementations, the following typechecks:

use rocket::http::RawStr;
use rocket::request::Form;

#[post("/<name>?<user..>")]
fn some_route(name: &RawStr, user: Form<User>)  { /* .. */ }

let uri = uri!(some_route: name = "hey", user = ("Robert Mike", "Bob"));
assert_eq!(uri.path(), "/hey");
assert_eq!(uri.query(), Some("name=Robert%20Mike&nickname=Bob"));

Associated Types

The resulting type of this conversion.

Required Methods

Converts a value of type T into a value of type Self::Target. The resulting value of type Self::Target will be rendered into a URI using its UriDisplay implementation.

Implementations on Foreign Types

impl<'x, 'a> FromUriParam<Path, &'x &'a Path> for &'a Path

impl<'x, P> FromUriParam<P, &'x mut Ipv6Addr> for Ipv6Addr where
    P: UriPart

impl<P> FromUriParam<P, u128> for u128 where
    P: UriPart

impl<'x, 'a, P> FromUriParam<P, &'x String> for &'a str where
    P: UriPart

impl<P> FromUriParam<P, String> for String where
    P: UriPart

impl<'x, 'a> FromUriParam<Path, &'x mut PathBuf> for &'a Path

impl<'a, P> FromUriParam<P, &'a str> for String where
    P: UriPart

impl<P> FromUriParam<P, f64> for f64 where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut u32> for u32 where
    P: UriPart

impl<'x, 'a, P> FromUriParam<P, &'x mut &'a str> for &'a str where
    P: UriPart

impl<P> FromUriParam<P, i128> for i128 where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x u32> for u32 where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x u64> for u64 where
    P: UriPart

impl<'a, P> FromUriParam<P, Cow<'a, str>> for Cow<'a, str> where
    P: UriPart

impl FromUriParam<Path, PathBuf> for PathBuf

impl<'x, P> FromUriParam<P, &'x u128> for u128 where
    P: UriPart

impl<'a, 'b> FromUriParam<Path, &'a &'b str> for PathBuf

A no cost conversion allowing an &&str to be used in place of a PathBuf.

impl<'x, P> FromUriParam<P, &'x i16> for i16 where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut i128> for i128 where
    P: UriPart

impl<P> FromUriParam<P, i8> for i8 where
    P: UriPart

impl<'x> FromUriParam<Path, &'x PathBuf> for PathBuf

impl<'x, P> FromUriParam<P, &'x i32> for i32 where
    P: UriPart

impl<'x, 'a, P> FromUriParam<P, &'x mut &'a str> for String where
    P: UriPart

impl<P> FromUriParam<P, u32> for u32 where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x Ipv6Addr> for Ipv6Addr where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut bool> for bool where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x f32> for f32 where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut i8> for i8 where
    P: UriPart

impl<'x, 'a> FromUriParam<Path, &'x PathBuf> for &'a Path

impl<P> FromUriParam<P, IpAddr> for IpAddr where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x usize> for usize where
    P: UriPart

impl<'x, 'a, P> FromUriParam<P, &'x Cow<'a, str>> for Cow<'a, str> where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut String> for String where
    P: UriPart

impl<P> FromUriParam<P, Ipv4Addr> for Ipv4Addr where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut i32> for i32 where
    P: UriPart

impl<P, A, E, T> FromUriParam<P, A> for Result<T, E> where
    P: UriPart,
    T: FromUriParam<P, A>, 

A no cost conversion allowing T to be used in place of an Result<T, E>.

impl<'x, 'a, P> FromUriParam<P, &'x &'a str> for String where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut IpAddr> for IpAddr where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut usize> for usize where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x i128> for i128 where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut f32> for f32 where
    P: UriPart

impl<P> FromUriParam<P, i64> for i64 where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut u64> for u64 where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x Ipv4Addr> for Ipv4Addr where
    P: UriPart

impl<P> FromUriParam<P, f32> for f32 where
    P: UriPart

impl<'x, 'a> FromUriParam<Path, &'x mut &'a Path> for &'a Path

impl<P> FromUriParam<P, usize> for usize where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut isize> for isize where
    P: UriPart

impl<'x, 'a, P> FromUriParam<P, &'x mut Cow<'a, str>> for Cow<'a, str> where
    P: UriPart

impl<'a, P> FromUriParam<P, String> for &'a str where
    P: UriPart

impl<'a> FromUriParam<Path, PathBuf> for &'a Path

impl<'x, P> FromUriParam<P, &'x f64> for f64 where
    P: UriPart

impl<P> FromUriParam<P, i32> for i32 where
    P: UriPart

impl<'x, 'a> FromUriParam<Path, &'x &'a Path> for PathBuf

impl<P> FromUriParam<P, i16> for i16 where
    P: UriPart

impl<P> FromUriParam<P, bool> for bool where
    P: UriPart

impl<P> FromUriParam<P, isize> for isize where
    P: UriPart

impl<P> FromUriParam<P, Ipv6Addr> for Ipv6Addr where
    P: UriPart

impl<P> FromUriParam<P, u8> for u8 where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut u128> for u128 where
    P: UriPart

impl<'x> FromUriParam<Path, &'x mut PathBuf> for PathBuf

impl<'x, P> FromUriParam<P, &'x mut f64> for f64 where
    P: UriPart

impl<'a, P> FromUriParam<P, &'a str> for &'a str where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut u16> for u16 where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut i16> for i16 where
    P: UriPart

impl<P> FromUriParam<P, u16> for u16 where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x bool> for bool where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x u8> for u8 where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x u16> for u16 where
    P: UriPart

impl<'a> FromUriParam<Path, &'a Path> for PathBuf

impl<'a> FromUriParam<Path, &'a str> for PathBuf

A no cost conversion allowing an &str to be used in place of a PathBuf.

impl<'x, P> FromUriParam<P, &'x mut Ipv4Addr> for Ipv4Addr where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x IpAddr> for IpAddr where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut u8> for u8 where
    P: UriPart

impl<'x, 'a, P> FromUriParam<P, &'x mut String> for &'a str where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x i8> for i8 where
    P: UriPart

impl<'x, 'a, P> FromUriParam<P, &'x &'a str> for &'a str where
    P: UriPart

impl<'a> FromUriParam<Path, &'a Path> for &'a Path

impl<'x, P> FromUriParam<P, &'x isize> for isize where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x mut i64> for i64 where
    P: UriPart

impl<'x, 'a> FromUriParam<Path, &'x mut &'a Path> for PathBuf

impl<P> FromUriParam<P, u64> for u64 where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x i64> for i64 where
    P: UriPart

impl<'x, P> FromUriParam<P, &'x String> for String where
    P: UriPart

impl<P, A, T> FromUriParam<P, A> for Option<T> where
    P: UriPart,
    T: FromUriParam<P, A>, 

A no cost conversion allowing any T to be used in place of an Option<T>.

Implementors

impl<'a, 'b, P> FromUriParam<P, &'a str> for &'b RawStr where
    P: UriPart

impl<'a, P> FromUriParam<P, &'a RawStr> for &'a RawStr where
    P: UriPart

impl<'a, P> FromUriParam<P, String> for &'a RawStr where
    P: UriPart

impl<'f, A, T: FromUriParam<Query, A> + FromForm<'f>> FromUriParam<Query, A> for Form<T>
[src]

impl<'f, A, T: FromUriParam<Query, A> + FromForm<'f>> FromUriParam<Query, A> for LenientForm<T>
[src]

impl<'x, 'a, 'b, P> FromUriParam<P, &'x &'a str> for &'b RawStr where
    P: UriPart

impl<'x, 'a, 'b, P> FromUriParam<P, &'x mut &'a str> for &'b RawStr where
    P: UriPart

impl<'x, 'a, P> FromUriParam<P, &'x &'a RawStr> for &'a RawStr where
    P: UriPart

impl<'x, 'a, P> FromUriParam<P, &'x String> for &'a RawStr where
    P: UriPart

impl<'x, 'a, P> FromUriParam<P, &'x mut &'a RawStr> for &'a RawStr where
    P: UriPart

impl<'x, 'a, P> FromUriParam<P, &'x mut String> for &'a RawStr where
    P: UriPart