client-api: Add helper methods to convert SystemTime from/to a HTTP date

crates/ruma-client-api/src/error.rs

@@ -6,17 +6,22 @@ use as_variant::as_variant;
 use bytes::{BufMut, Bytes};
 use ruma_common::{
     api::{
-        error::{FromHttpResponseError, IntoHttpError, MatrixErrorBody},
+        error::{
+            FromHttpResponseError, HeaderDeserializationError, HeaderSerializationError,
+            IntoHttpError, MatrixErrorBody,
+        },
         EndpointError, OutgoingResponse,
     },
     RoomVersionId,
 };
 use serde::{Deserialize, Serialize};
 use serde_json::{from_slice as from_json_slice, Value as JsonValue};
-use thiserror::Error;
+use web_time::{Duration, SystemTime};
-use web_time::{Duration, SystemTime, UNIX_EPOCH};
 
-use crate::PrivOwnedStr;
+use crate::{
+    http_headers::{http_date_to_system_time, system_time_to_http_date},
+    PrivOwnedStr,
+};
 
 /// Deserialize and Serialize implementations for ErrorKind.
 /// Separate module because it's a lot of code.
@@ -372,9 +377,8 @@ impl EndpointError for Error {
                     ErrorKind::LimitExceeded { retry_after } => {
                         // The Retry-After header takes precedence over the retry_after_ms field in
                         // the body.
-                        if let Some(retry_after_header) = headers
+                        if let Some(Ok(retry_after_header)) =
-                            .get(http::header::RETRY_AFTER)
+                            headers.get(http::header::RETRY_AFTER).map(RetryAfter::try_from)
-                            .and_then(RetryAfter::from_header_value)
                         {
                             *retry_after = Some(retry_after_header);
                         }
@@ -567,59 +571,31 @@ pub enum RetryAfter {
     DateTime(SystemTime),
 }
 
-impl RetryAfter {
+impl TryFrom<&http::HeaderValue> for RetryAfter {
-    fn from_header_value(value: &http::HeaderValue) -> Option<Self> {
+    type Error = HeaderDeserializationError;
-        let bytes = value.as_bytes();
 
-        if bytes.iter().all(|b| b.is_ascii_digit()) {
+    fn try_from(value: &http::HeaderValue) -> Result<Self, Self::Error> {
+        if value.as_bytes().iter().all(|b| b.is_ascii_digit()) {
             // It should be a duration.
-            Some(Self::Delay(Duration::from_secs(u64::from_str(value.to_str().ok()?).ok()?)))
+            Ok(Self::Delay(Duration::from_secs(u64::from_str(value.to_str()?)?)))
         } else {
             // It should be a date.
-            let ts = date_header::parse(bytes).ok()?;
+            Ok(Self::DateTime(http_date_to_system_time(value)?))
-            Some(Self::DateTime(UNIX_EPOCH.checked_add(Duration::from_secs(ts))?))
         }
     }
 }
 
 impl TryFrom<&RetryAfter> for http::HeaderValue {
-    type Error = RetryAfterInvalidDateTime;
+    type Error = HeaderSerializationError;
 
     fn try_from(value: &RetryAfter) -> Result<Self, Self::Error> {
         match value {
             RetryAfter::Delay(duration) => Ok(duration.as_secs().into()),
-            RetryAfter::DateTime(time) => {
+            RetryAfter::DateTime(time) => system_time_to_http_date(time),
-                let mut buffer = [0; 29];
-                let duration =
-                    time.duration_since(UNIX_EPOCH).map_err(|_| RetryAfterInvalidDateTime)?;
-                date_header::format(duration.as_secs(), &mut buffer)
-                    .map_err(|_| RetryAfterInvalidDateTime)?;
-                let value = http::HeaderValue::from_bytes(&buffer)
-                    .expect("date_header should produce a valid header value");
-
-                Ok(value)
-            }
         }
     }
 }
 
-/// An error when converting a [`RetryAfter`] to a [`http::HeaderValue`].
-///
-/// Happens when the `DateTime` is too far in the past (before the Unix epoch) or the
-/// future (after the year 9999).
-#[derive(Debug, Error)]
-#[allow(clippy::exhaustive_structs)]
-#[error(
-    "Retry-After header serialization failed: the datetime is too far in the past or the future"
-)]
-pub struct RetryAfterInvalidDateTime;
-
-impl From<RetryAfterInvalidDateTime> for IntoHttpError {
-    fn from(_value: RetryAfterInvalidDateTime) -> Self {
-        IntoHttpError::RetryAfterInvalidDatetime
-    }
-}
-
 /// Extension trait for `FromHttpResponseError<ruma_client_api::Error>`.
 pub trait FromHttpResponseErrorExt {
     /// If `self` is a server error in the `errcode` + `error` format expected

crates/ruma-client-api/src/http_headers.rs

@@ -1,10 +1,40 @@
-//! Custom HTTP headers not defined in the `http` crate.
+//! Helpers for HTTP headers with the `http` crate.
 #![allow(clippy::declare_interior_mutable_const)]
 
-use http::header::HeaderName;
+use http::{header::HeaderName, HeaderValue};
+use ruma_common::api::error::{HeaderDeserializationError, HeaderSerializationError};
+use web_time::{Duration, SystemTime, UNIX_EPOCH};
 
 /// The [`Cross-Origin-Resource-Policy`] HTTP response header.
 ///
 /// [`Cross-Origin-Resource-Policy`]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Resource-Policy
 pub const CROSS_ORIGIN_RESOURCE_POLICY: HeaderName =
     HeaderName::from_static("cross-origin-resource-policy");
+
+/// Convert as `SystemTime` to a HTTP date header value.
+pub fn system_time_to_http_date(
+    time: &SystemTime,
+) -> Result<HeaderValue, HeaderSerializationError> {
+    let mut buffer = [0; 29];
+
+    let duration =
+        time.duration_since(UNIX_EPOCH).map_err(|_| HeaderSerializationError::InvalidHttpDate)?;
+    date_header::format(duration.as_secs(), &mut buffer)
+        .map_err(|_| HeaderSerializationError::InvalidHttpDate)?;
+
+    Ok(http::HeaderValue::from_bytes(&buffer)
+        .expect("date_header should produce a valid header value"))
+}
+
+/// Convert a header value representing a HTTP date to a `SystemTime`.
+pub fn http_date_to_system_time(
+    value: &HeaderValue,
+) -> Result<SystemTime, HeaderDeserializationError> {
+    let bytes = value.as_bytes();
+
+    let ts = date_header::parse(bytes).map_err(|_| HeaderDeserializationError::InvalidHttpDate)?;
+
+    UNIX_EPOCH
+        .checked_add(Duration::from_secs(ts))
+        .ok_or(HeaderDeserializationError::InvalidHttpDate)
+}

crates/ruma-common/CHANGELOG.md

@@ -5,6 +5,7 @@ Bug fixes:
 - Allow to deserialize `Ruleset` with missing fields.
 
 Breaking changes:
+
 - The power levels fields in `PushConditionRoomCtx` are grouped in an optional `power_levels` field.
   If the field is missing, push rules that depend on it will never match. However, this allows to
   match the `.m.rule.invite_for_me` push rule because usually the `invite_state` doesn't include
@@ -14,6 +15,7 @@ Breaking changes:
 - `deserialize_as_f64_or_string` has been extended to also support parsing integers, and renamed to
   `deserialize_as_number_or_string` to reflect that.
 - The http crate had a major version bump to version 1.1
+- `IntoHttpError::Header` now contains a `HeaderSerializationError`
 
 Improvements:
 

crates/ruma-common/src/api/error.rs

@@ -2,7 +2,7 @@
 //! converting between http requests / responses and ruma's representation of
 //! matrix API requests / responses.
 
-use std::{error::Error as StdError, fmt, sync::Arc};
+use std::{error::Error as StdError, fmt, num::ParseIntError, sync::Arc};
 
 use bytes::{BufMut, Bytes};
 use serde_json::{from_slice as from_json_slice, Value as JsonValue};
@@ -127,20 +127,19 @@ pub enum IntoHttpError {
 
     /// Header serialization failed.
     #[error("header serialization failed: {0}")]
-    Header(#[from] http::header::InvalidHeaderValue),
+    Header(#[from] HeaderSerializationError),
-
-    /// Retry-After header serialization failed because the datetime provided is after the year
-    /// 9999.
-    #[error(
-        "Retry-After header serialization failed: the year of the datetime is bigger than 9999"
-    )]
-    RetryAfterInvalidDatetime,
 
     /// HTTP request construction failed.
     #[error("HTTP request construction failed: {0}")]
     Http(#[from] http::Error),
 }
 
+impl From<http::header::InvalidHeaderValue> for IntoHttpError {
+    fn from(value: http::header::InvalidHeaderValue) -> Self {
+        Self::Header(value.into())
+    }
+}
+
 /// An error when converting a http request to one of ruma's endpoint-specific request types.
 #[derive(Debug, Error)]
 #[non_exhaustive]
@@ -258,13 +257,21 @@ impl From<http::header::ToStrError> for DeserializationError {
     }
 }
 
-/// An error with the http headers.
+/// An error when deserializing the HTTP headers.
 #[derive(Debug, Error)]
 #[non_exhaustive]
 pub enum HeaderDeserializationError {
     /// Failed to convert `http::header::HeaderValue` to `str`.
     #[error("{0}")]
-    ToStrError(http::header::ToStrError),
+    ToStrError(#[from] http::header::ToStrError),
+
+    /// Failed to convert `http::header::HeaderValue` to an integer.
+    #[error("{0}")]
+    ParseIntError(#[from] ParseIntError),
+
+    /// Failed to parse a HTTP date from a `http::header::Value`.
+    #[error("failed to parse HTTP date")]
+    InvalidHttpDate,
 
     /// The given required header is missing.
     #[error("missing header `{0}`")]
@@ -303,3 +310,19 @@ impl fmt::Display for IncorrectArgumentCount {
 }
 
 impl StdError for IncorrectArgumentCount {}
+
+/// An error when serializing the HTTP headers.
+#[derive(Debug, Error)]
+#[non_exhaustive]
+pub enum HeaderSerializationError {
+    /// Failed to convert a header value to `http::header::HeaderValue`.
+    #[error(transparent)]
+    ToHeaderValue(#[from] http::header::InvalidHeaderValue),
+
+    /// The `SystemTime` could not be converted to a HTTP date.
+    ///
+    /// This only happens if the `SystemTime` provided is too far in the past (before the Unix
+    /// epoch) or the future (after the year 9999).
+    #[error("invalid HTTP date")]
+    InvalidHttpDate,
+}