http_message_signatures/component

RFC 9421 §2 component identifiers, canonicalization, and signature base assembly.

Covers: §2.1 (HTTP fields), §2.2.1-§2.2.9 (derived components, origin-form @request-target only), and §2.5 (signature base creation). Structured-field component parameters (sf, key, bs), trailer fields (tr), and request-response binding (req) are out of scope — see the README.

Types

ComponentError

</>

pub type ComponentError {
  HeaderNotFound(String)
  QueryParamNotFound(String)
  NotARequestComponent(DerivedComponent)
  NotAResponseComponent
  InvalidTargetUri(String)
}

Constructors

```
HeaderNotFound(String)
```
```
QueryParamNotFound(String)
```
```
NotARequestComponent(DerivedComponent)
```
```
NotAResponseComponent
```
```
InvalidTargetUri(String)
```

ComponentIdentifier

</>

pub type ComponentIdentifier {
  Derived(DerivedComponent)
  Field(name: String)
}

Constructors

```
Derived(DerivedComponent)
```
```
Field(name: String)
```

DerivedComponent

</>

pub type DerivedComponent {
  Method
  TargetUri
  Authority
  Scheme
  RequestTarget
  Path
  Query
  QueryParam(name: String)
  Status
}

Constructors

```
Method
```
```
TargetUri
```
```
Authority
```
```
Scheme
```
```
RequestTarget
```
```
Path
```
```
Query
```
```
QueryParam(name: String)
```
```
Status
```

Values

component_value

</>

pub fn component_value(
  id: ComponentIdentifier,
  message: message.Message,
) -> Result(String, ComponentError)

Resolves a component identifier to its canonicalized string value for the given message, per RFC 9421 §2.1 (HTTP fields) and §2.2 (derived components).

identifier_to_element

</>

pub fn identifier_to_element(
  id: ComponentIdentifier,
) -> types.Element

Renders a component identifier as a Structured Fields Element, per RFC 9421 §2.5 — the component name as a BareString Item, with any component parameters (only ;name= for @query-param is supported).

identifier_to_string

</>

pub fn identifier_to_string(id: ComponentIdentifier) -> String

The strict Structured Fields serialization of a component identifier, e.g. "@method" or "@query-param";name="baz".

signature_base

</>

pub fn signature_base(
  components: List(ComponentIdentifier),
  message: message.Message,
  signature_params_element: types.Element,
) -> Result(String, ComponentError)

Assembles the signature base (RFC 9421 §2.5): one line per covered component, identifier: value, followed by the @signature-params line, joined with \n (no trailing newline).