package wasi:http@0.3.0-rc-2026-03-15;

/// This interface defines all of the types and methods for implementing HTTP
/// Requests and Responses, as well as their headers, trailers, and bodies.
@since(version = 0.3.0-rc-2026-03-15)
interface types {
  use wasi:clocks/types@0.3.0-rc-2026-03-15.{duration};

  /// This type corresponds to HTTP standard Methods.
  @since(version = 0.3.0-rc-2026-03-15)
  variant method {
    get,
    head,
    post,
    put,
    delete,
    connect,
    options,
    trace,
    patch,
    other(string),
  }

  /// This type corresponds to HTTP standard Related Schemes.
  @since(version = 0.3.0-rc-2026-03-15)
  variant scheme {
    HTTP,
    HTTPS,
    other(string),
  }

  /// Defines the case payload type for `DNS-error` above:
  @since(version = 0.3.0-rc-2026-03-15)
  record DNS-error-payload {
    rcode: option<string>,
    info-code: option<u16>,
  }

  /// Defines the case payload type for `TLS-alert-received` above:
  @since(version = 0.3.0-rc-2026-03-15)
  record TLS-alert-received-payload {
    alert-id: option<u8>,
    alert-message: option<string>,
  }

  /// Defines the case payload type for `HTTP-response-{header,trailer}-size` above:
  @since(version = 0.3.0-rc-2026-03-15)
  record field-size-payload {
    field-name: option<string>,
    field-size: option<u32>,
  }

  /// These cases are inspired by the IANA HTTP Proxy Error Types:
  ///   <https://www.iana.org/assignments/http-proxy-status/http-proxy-status.xhtml#table-http-proxy-error-types>
  @since(version = 0.3.0-rc-2026-03-15)
  variant error-code {
    DNS-timeout,
    DNS-error(DNS-error-payload),
    destination-not-found,
    destination-unavailable,
    destination-IP-prohibited,
    destination-IP-unroutable,
    connection-refused,
    connection-terminated,
    connection-timeout,
    connection-read-timeout,
    connection-write-timeout,
    connection-limit-reached,
    TLS-protocol-error,
    TLS-certificate-error,
    TLS-alert-received(TLS-alert-received-payload),
    HTTP-request-denied,
    HTTP-request-length-required,
    HTTP-request-body-size(option<u64>),
    HTTP-request-method-invalid,
    HTTP-request-URI-invalid,
    HTTP-request-URI-too-long,
    HTTP-request-header-section-size(option<u32>),
    HTTP-request-header-size(option<field-size-payload>),
    HTTP-request-trailer-section-size(option<u32>),
    HTTP-request-trailer-size(field-size-payload),
    HTTP-response-incomplete,
    HTTP-response-header-section-size(option<u32>),
    HTTP-response-header-size(field-size-payload),
    HTTP-response-body-size(option<u64>),
    HTTP-response-trailer-section-size(option<u32>),
    HTTP-response-trailer-size(field-size-payload),
    HTTP-response-transfer-coding(option<string>),
    HTTP-response-content-coding(option<string>),
    HTTP-response-timeout,
    HTTP-upgrade-failed,
    HTTP-protocol-error,
    loop-detected,
    configuration-error,
    /// This is a catch-all error for anything that doesn't fit cleanly into a
    /// more specific case. It also includes an optional string for an
    /// unstructured description of the error. Users should not depend on the
    /// string for diagnosing errors, as it's not required to be consistent
    /// between implementations.
    internal-error(option<string>),
  }

  /// This type enumerates the different kinds of errors that may occur when
  /// setting or appending to a `fields` resource.
  @since(version = 0.3.0-rc-2026-03-15)
  variant header-error {
    /// This error indicates that a `field-name` or `field-value` was
    /// syntactically invalid when used with an operation that sets headers in a
    /// `fields`.
    invalid-syntax,
    /// This error indicates that a forbidden `field-name` was used when trying
    /// to set a header in a `fields`.
    forbidden,
    /// This error indicates that the operation on the `fields` was not
    /// permitted because the fields are immutable.
    immutable,
    /// This error indicates that the operation would exceed an
    /// implementation-defined limit on field sizes. This may apply to
    /// an individual `field-value`, a single `field-name` plus all its
    /// values, or the total aggregate size of all fields.
    size-exceeded,
    /// This is a catch-all error for anything that doesn't fit cleanly into a
    /// more specific case. Implementations can use this to extend the error
    /// type without breaking existing code. It also includes an optional
    /// string for an unstructured description of the error. Users should not
    /// depend on the string for diagnosing errors, as it's not required to be
    /// consistent between implementations.
    other(option<string>),
  }

  /// This type enumerates the different kinds of errors that may occur when
  /// setting fields of a `request-options` resource.
  @since(version = 0.3.0-rc-2026-03-15)
  variant request-options-error {
    /// Indicates the specified field is not supported by this implementation.
    not-supported,
    /// Indicates that the operation on the `request-options` was not permitted
    /// because it is immutable.
    immutable,
    /// This is a catch-all error for anything that doesn't fit cleanly into a
    /// more specific case. Implementations can use this to extend the error
    /// type without breaking existing code. It also includes an optional
    /// string for an unstructured description of the error. Users should not
    /// depend on the string for diagnosing errors, as it's not required to be
    /// consistent between implementations.
    other(option<string>),
  }

  /// Field names are always strings.
  ///
  /// Field names should always be treated as case insensitive by the `fields`
  /// resource for the purposes of equality checking.
  @since(version = 0.3.0-rc-2026-03-15)
  type field-name = string;

  /// Field values should always be ASCII strings. However, in
  /// reality, HTTP implementations often have to interpret malformed values,
  /// so they are provided as a list of bytes.
  @since(version = 0.3.0-rc-2026-03-15)
  type field-value = list<u8>;

  /// This following block defines the `fields` resource which corresponds to
  /// HTTP standard Fields. Fields are a common representation used for both
  /// Headers and Trailers.
  ///
  /// A `fields` may be mutable or immutable. A `fields` created using the
  /// constructor, `from-list`, or `clone` will be mutable, but a `fields`
  /// resource given by other means (including, but not limited to,
  /// `request.headers`) might be be immutable. In an immutable fields, the
  /// `set`, `append`, and `delete` operations will fail with
  /// `header-error.immutable`.
  ///
  /// A `fields` resource should store `field-name`s and `field-value`s in their
  /// original casing used to construct or mutate the `fields` resource. The `fields`
  /// resource should use that original casing when serializing the fields for
  /// transport or when returning them from a method.
  ///
  /// Implementations may impose limits on individual field values and on total
  /// aggregate field section size. Operations that would exceed these limits
  /// fail with `header-error.size-exceeded`
  @since(version = 0.3.0-rc-2026-03-15)
  resource fields {
    /// Construct an empty HTTP Fields.
    ///
    /// The resulting `fields` is mutable.
    constructor();
    /// Construct an HTTP Fields.
    ///
    /// The resulting `fields` is mutable.
    ///
    /// The list represents each name-value pair in the Fields. Names
    /// which have multiple values are represented by multiple entries in this
    /// list with the same name.
    ///
    /// The tuple is a pair of the field name, represented as a string, and
    /// Value, represented as a list of bytes. In a valid Fields, all names
    /// and values are valid UTF-8 strings. However, values are not always
    /// well-formed, so they are represented as a raw list of bytes.
    ///
    /// An error result will be returned if any header or value was
    /// syntactically invalid, if a header was forbidden, or if the
    /// entries would exceed an implementation size limit.
    from-list: static func(entries: list<tuple<field-name, field-value>>) -> result<fields, header-error>;
    /// Get all of the values corresponding to a name. If the name is not present
    /// in this `fields`, an empty list is returned. However, if the name is
    /// present but empty, this is represented by a list with one or more
    /// empty field-values present.
    get: func(name: field-name) -> list<field-value>;
    /// Returns `true` when the name is present in this `fields`. If the name is
    /// syntactically invalid, `false` is returned.
    has: func(name: field-name) -> bool;
    /// Set all of the values for a name. Clears any existing values for that
    /// name, if they have been set.
    ///
    /// Fails with `header-error.immutable` if the `fields` are immutable.
    ///
    /// Fails with `header-error.size-exceeded` if the name or values would
    /// exceed an implementation-defined size limit.
    set: func(name: field-name, value: list<field-value>) -> result<_, header-error>;
    /// Delete all values for a name. Does nothing if no values for the name
    /// exist.
    ///
    /// Fails with `header-error.immutable` if the `fields` are immutable.
    delete: func(name: field-name) -> result<_, header-error>;
    /// Delete all values for a name. Does nothing if no values for the name
    /// exist.
    ///
    /// Returns all values previously corresponding to the name, if any.
    ///
    /// Fails with `header-error.immutable` if the `fields` are immutable.
    get-and-delete: func(name: field-name) -> result<list<field-value>, header-error>;
    /// Append a value for a name. Does not change or delete any existing
    /// values for that name.
    ///
    /// Fails with `header-error.immutable` if the `fields` are immutable.
    ///
    /// Fails with `header-error.size-exceeded` if the value would exceed
    /// an implementation-defined size limit.
    append: func(name: field-name, value: field-value) -> result<_, header-error>;
    /// Retrieve the full set of names and values in the Fields. Like the
    /// constructor, the list represents each name-value pair.
    ///
    /// The outer list represents each name-value pair in the Fields. Names
    /// which have multiple values are represented by multiple entries in this
    /// list with the same name.
    ///
    /// The names and values are always returned in the original casing and in
    /// the order in which they will be serialized for transport.
    copy-all: func() -> list<tuple<field-name, field-value>>;
    /// Make a deep copy of the Fields. Equivalent in behavior to calling the
    /// `fields` constructor on the return value of `copy-all`. The resulting
    /// `fields` is mutable.
    clone: func() -> fields;
  }

  /// Headers is an alias for Fields.
  @since(version = 0.3.0-rc-2026-03-15)
  type headers = fields;

  /// Trailers is an alias for Fields.
  @since(version = 0.3.0-rc-2026-03-15)
  type trailers = fields;

  /// Represents an HTTP Request.
  @since(version = 0.3.0-rc-2026-03-15)
  resource request {
    /// Construct a new `request` with a default `method` of `GET`, and
    /// `none` values for `path-with-query`, `scheme`, and `authority`.
    ///
    /// `headers` is the HTTP Headers for the Request.
    ///
    /// `contents` is the optional body content stream with `none`
    /// representing a zero-length content stream.
    /// Once it is closed, `trailers` future must resolve to a result.
    /// If `trailers` resolves to an error, underlying connection
    /// will be closed immediately.
    ///
    /// `options` is optional `request-options` resource to be used
    /// if the request is sent over a network connection.
    ///
    /// It is possible to construct, or manipulate with the accessor functions
    /// below, a `request` with an invalid combination of `scheme`
    /// and `authority`, or `headers` which are not permitted to be sent.
    /// It is the obligation of the `handler.handle` implementation
    /// to reject invalid constructions of `request`.
    ///
    /// The returned future resolves to result of transmission of this request.
    new: static func(headers: headers, contents: option<stream<u8>>, trailers: future<result<option<trailers>, error-code>>, options: option<request-options>) -> tuple<request, future<result<_, error-code>>>;
    /// Get the Method for the Request.
    get-method: func() -> method;
    /// Set the Method for the Request. Fails if the string present in a
    /// `method.other` argument is not a syntactically valid method.
    set-method: func(method: method) -> result;
    /// Get the combination of the HTTP Path and Query for the Request.  When
    /// `none`, this represents an empty Path and empty Query.
    get-path-with-query: func() -> option<string>;
    /// Set the combination of the HTTP Path and Query for the Request.  When
    /// `none`, this represents an empty Path and empty Query. Fails is the
    /// string given is not a syntactically valid path and query uri component.
    set-path-with-query: func(path-with-query: option<string>) -> result;
    /// Get the HTTP Related Scheme for the Request. When `none`, the
    /// implementation may choose an appropriate default scheme.
    get-scheme: func() -> option<scheme>;
    /// Set the HTTP Related Scheme for the Request. When `none`, the
    /// implementation may choose an appropriate default scheme. Fails if the
    /// string given is not a syntactically valid uri scheme.
    set-scheme: func(scheme: option<scheme>) -> result;
    /// Get the authority of the Request's target URI. A value of `none` may be used
    /// with Related Schemes which do not require an authority. The HTTP and
    /// HTTPS schemes always require an authority.
    get-authority: func() -> option<string>;
    /// Set the authority of the Request's target URI. A value of `none` may be used
    /// with Related Schemes which do not require an authority. The HTTP and
    /// HTTPS schemes always require an authority. Fails if the string given is
    /// not a syntactically valid URI authority.
    set-authority: func(authority: option<string>) -> result;
    /// Get the `request-options` to be associated with this request
    ///
    /// The returned `request-options` resource is immutable: `set-*` operations
    /// will fail if invoked.
    ///
    /// This `request-options` resource is a child: it must be dropped before
    /// the parent `request` is dropped, or its ownership is transferred to
    /// another component by e.g. `handler.handle`.
    get-options: func() -> option<request-options>;
    /// Get the headers associated with the Request.
    ///
    /// The returned `headers` resource is immutable: `set`, `append`, and
    /// `delete` operations will fail with `header-error.immutable`.
    get-headers: func() -> headers;
    /// Get body of the Request.
    ///
    /// Stream returned by this method represents the contents of the body.
    /// Once the stream is reported as closed, callers should await the returned
    /// future to determine whether the body was received successfully.
    /// The future will only resolve after the stream is reported as closed.
    ///
    /// This function takes a `res` future as a parameter, which can be used to
    /// communicate an error in handling of the request.
    ///
    /// Note that function will move the `request`, but references to headers or
    /// request options acquired from it previously will remain valid.
    consume-body: static func(this: request, res: future<result<_, error-code>>) -> tuple<stream<u8>, future<result<option<trailers>, error-code>>>;
  }

  /// Parameters for making an HTTP Request. Each of these parameters is
  /// currently an optional timeout applicable to the transport layer of the
  /// HTTP protocol.
  ///
  /// These timeouts are separate from any the user may use to bound an
  /// asynchronous call.
  @since(version = 0.3.0-rc-2026-03-15)
  resource request-options {
    /// Construct a default `request-options` value.
    constructor();
    /// The timeout for the initial connect to the HTTP Server.
    get-connect-timeout: func() -> option<duration>;
    /// Set the timeout for the initial connect to the HTTP Server. An error
    /// return value indicates that this timeout is not supported or that this
    /// handle is immutable.
    set-connect-timeout: func(duration: option<duration>) -> result<_, request-options-error>;
    /// The timeout for receiving the first byte of the Response body.
    get-first-byte-timeout: func() -> option<duration>;
    /// Set the timeout for receiving the first byte of the Response body. An
    /// error return value indicates that this timeout is not supported or that
    /// this handle is immutable.
    set-first-byte-timeout: func(duration: option<duration>) -> result<_, request-options-error>;
    /// The timeout for receiving subsequent chunks of bytes in the Response
    /// body stream.
    get-between-bytes-timeout: func() -> option<duration>;
    /// Set the timeout for receiving subsequent chunks of bytes in the Response
    /// body stream. An error return value indicates that this timeout is not
    /// supported or that this handle is immutable.
    set-between-bytes-timeout: func(duration: option<duration>) -> result<_, request-options-error>;
    /// Make a deep copy of the `request-options`.
    /// The resulting `request-options` is mutable.
    clone: func() -> request-options;
  }

  /// This type corresponds to the HTTP standard Status Code.
  @since(version = 0.3.0-rc-2026-03-15)
  type status-code = u16;

  /// Represents an HTTP Response.
  @since(version = 0.3.0-rc-2026-03-15)
  resource response {
    /// Construct a new `response`, with a default `status-code` of `200`.
    /// If a different `status-code` is needed, it must be set via the
    /// `set-status-code` method.
    ///
    /// `headers` is the HTTP Headers for the Response.
    ///
    /// `contents` is the optional body content stream with `none`
    /// representing a zero-length content stream.
    /// Once it is closed, `trailers` future must resolve to a result.
    /// If `trailers` resolves to an error, underlying connection
    /// will be closed immediately.
    ///
    /// The returned future resolves to result of transmission of this response.
    new: static func(headers: headers, contents: option<stream<u8>>, trailers: future<result<option<trailers>, error-code>>) -> tuple<response, future<result<_, error-code>>>;
    /// Get the HTTP Status Code for the Response.
    get-status-code: func() -> status-code;
    /// Set the HTTP Status Code for the Response. Fails if the status-code
    /// given is not a valid http status code.
    set-status-code: func(status-code: status-code) -> result;
    /// Get the headers associated with the Response.
    ///
    /// The returned `headers` resource is immutable: `set`, `append`, and
    /// `delete` operations will fail with `header-error.immutable`.
    get-headers: func() -> headers;
    /// Get body of the Response.
    ///
    /// Stream returned by this method represents the contents of the body.
    /// Once the stream is reported as closed, callers should await the returned
    /// future to determine whether the body was received successfully.
    /// The future will only resolve after the stream is reported as closed.
    ///
    /// This function takes a `res` future as a parameter, which can be used to
    /// communicate an error in handling of the response.
    ///
    /// Note that function will move the `response`, but references to headers
    /// acquired from it previously will remain valid.
    consume-body: static func(this: response, res: future<result<_, error-code>>) -> tuple<stream<u8>, future<result<option<trailers>, error-code>>>;
  }
}

/// This interface defines a handler of HTTP Requests.
///
/// In a `wasi:http/service` this interface is exported to respond to an
/// incoming HTTP Request with a Response.
///
/// In `wasi:http/middleware` this interface is both exported and imported as
/// the "downstream" and "upstream" directions of the middleware chain.
@since(version = 0.3.0-rc-2026-03-15)
interface handler {
  use types.{request, response, error-code};

  /// This function may be called with either an incoming request read from the
  /// network or a request synthesized or forwarded by another component.
  handle: async func(request: request) -> result<response, error-code>;
}

/// This interface defines an HTTP client for sending "outgoing" requests.
///
/// Most components are expected to import this interface to provide the
/// capability to send HTTP requests to arbitrary destinations on a network.
///
/// The type signature of `client.send` is the same as `handler.handle`. This
/// duplication is currently necessary because some Component Model tooling
/// (including WIT itself) is unable to represent a component importing two
/// instances of the same interface. A `client.send` import may be linked
/// directly to a `handler.handle` export to bypass the network.
@since(version = 0.3.0-rc-2026-03-15)
interface client {
  use types.{request, response, error-code};

  /// This function may be used to either send an outgoing request over the
  /// network or to forward it to another component.
  send: async func(request: request) -> result<response, error-code>;
}

/// The `wasi:http/service` world captures a broad category of HTTP services
/// including web applications, API servers, and proxies. It may be `include`d
/// in more specific worlds such as `wasi:http/middleware`.
@since(version = 0.3.0-rc-2026-03-15)
world service {
  import wasi:cli/types@0.3.0-rc-2026-03-15;
  import wasi:cli/stdout@0.3.0-rc-2026-03-15;
  import wasi:cli/stderr@0.3.0-rc-2026-03-15;
  import wasi:cli/stdin@0.3.0-rc-2026-03-15;
  import wasi:clocks/types@0.3.0-rc-2026-03-15;
  import types;
  import client;
  import wasi:clocks/monotonic-clock@0.3.0-rc-2026-03-15;
  import wasi:clocks/system-clock@0.3.0-rc-2026-03-15;
  @unstable(feature = clocks-timezone)
  import wasi:clocks/timezone@0.3.0-rc-2026-03-15;
  import wasi:random/random@0.3.0-rc-2026-03-15;
  import wasi:random/insecure@0.3.0-rc-2026-03-15;
  import wasi:random/insecure-seed@0.3.0-rc-2026-03-15;

  export handler;
}
/// The `wasi:http/middleware` world captures HTTP services that forward HTTP
/// Requests to another handler.
///
/// Components may implement this world to allow them to participate in handler
/// "chains" where a `request` flows through handlers on its way to some terminal
/// `service` and corresponding `response` flows in the opposite direction.
@since(version = 0.3.0-rc-2026-03-15)
world middleware {
  import wasi:clocks/types@0.3.0-rc-2026-03-15;
  import types;
  import handler;
  import wasi:cli/types@0.3.0-rc-2026-03-15;
  import wasi:cli/stdout@0.3.0-rc-2026-03-15;
  import wasi:cli/stderr@0.3.0-rc-2026-03-15;
  import wasi:cli/stdin@0.3.0-rc-2026-03-15;
  import client;
  import wasi:clocks/monotonic-clock@0.3.0-rc-2026-03-15;
  import wasi:clocks/system-clock@0.3.0-rc-2026-03-15;
  @unstable(feature = clocks-timezone)
  import wasi:clocks/timezone@0.3.0-rc-2026-03-15;
  import wasi:random/random@0.3.0-rc-2026-03-15;
  import wasi:random/insecure@0.3.0-rc-2026-03-15;
  import wasi:random/insecure-seed@0.3.0-rc-2026-03-15;

  export handler;
}
