Merge pull request #5 from pfz4/responders

Implements axum responses for all of the htmx response headers; allowing users to simply and safely apply htmx headers to responses from their routes.

Cargo.toml

@@ -13,6 +13,7 @@ edition = "2021"
 [features]
 default = [ ]
 guards = ["tower", "futures-core", "pin-project-lite"]
+serde = [ "dep:serde", "dep:serde_json" ]
 
 [dependencies]
 axum = { git = "https://github.com/tokio-rs/axum", branch = "main", default-features = false }
@@ -21,3 +22,7 @@ axum = { git = "https://github.com/tokio-rs/axum", branch = "main", default-feat
 tower = { version = "0.4", default-features = false, optional = true }
 futures-core = { version = "0.3", optional = true }
 pin-project-lite = { version = "0.2", optional = true }
+
+serde = { version = "1.0", features = ["derive"], optional = true }
+serde_json = { version = "1.0", optional = true }
+

src/lib.rs

@@ -4,8 +4,10 @@ pub mod extractors;
 #[cfg(feature = "guards")]
 pub mod guard;
 pub mod headers;
+pub mod responders;
 
 pub use extractors::*;
 #[cfg(feature = "guards")]
 pub use guard::*;
 pub use headers::*;
+pub use responders::*;

src/responders.rs

@@ -0,0 +1,329 @@
+use std::convert::Infallible;
+
+use axum::{
+    http::{header::InvalidHeaderValue, HeaderValue, StatusCode, Uri},
+    response::{IntoResponse, IntoResponseParts, ResponseParts},
+};
+
+use crate::headers;
+
+#[cfg(feature = "serde")]
+pub mod serde;
+
+const HX_SWAP_INNER_HTML: &str = "innerHTML";
+const HX_SWAP_OUTER_HTML: &str = "outerHTML";
+const HX_SWAP_BEFORE_BEGIN: &str = "beforebegin";
+const HX_SWAP_AFTER_BEGIN: &str = "afterbegin";
+const HX_SWAP_BEFORE_END: &str = "beforeend";
+const HX_SWAP_AFTER_END: &str = "afterend";
+const HX_SWAP_DELETE: &str = "delete";
+const HX_SWAP_NONE: &str = "none";
+
+/// The `HX-Location` header.
+///
+/// This response header can be used to trigger a client side redirection without reloading the whole page.
+///
+/// Will fail if the supplied Uri contains characters that are not visible ASCII (32-127).
+#[derive(Debug, Clone)]
+pub struct HxLocation(pub Uri);
+
+impl IntoResponseParts for HxLocation {
+    type Error = HxError;
+
+    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        res.headers_mut().insert(
+            headers::HX_LOCATION,
+            HeaderValue::from_maybe_shared(self.0.to_string())?,
+        );
+        Ok(res)
+    }
+}
+
+/// The `HX-Push-Url` header.
+///
+/// Pushes a new url into the history stack.
+///
+/// Will fail if the supplied Uri contains characters that are not visible ASCII (32-127).
+#[derive(Debug, Clone)]
+pub struct HxPushUrl(pub Uri);
+
+impl IntoResponseParts for HxPushUrl {
+    type Error = HxError;
+
+    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        res.headers_mut().insert(
+            headers::HX_PUSH_URL,
+            HeaderValue::from_maybe_shared(self.0.to_string())?,
+        );
+        Ok(res)
+    }
+}
+
+/// The `HX-Redirect` header.
+///
+/// Can be used to do a client-side redirect to a new location.
+///
+/// Will fail if the supplied Uri contains characters that are not visible ASCII (32-127).
+#[derive(Debug, Clone)]
+pub struct HxRedirect(pub Uri);
+
+impl IntoResponseParts for HxRedirect {
+    type Error = HxError;
+
+    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        res.headers_mut().insert(
+            headers::HX_REDIRECT,
+            HeaderValue::from_maybe_shared(self.0.to_string())?,
+        );
+        Ok(res)
+    }
+}
+
+/// The `HX-Refresh`header.
+///
+/// If set to `true` the client-side will do a full refresh of the page.
+///
+/// This responder will never fail.
+#[derive(Debug, Copy, Clone)]
+pub struct HxRefresh(pub bool);
+
+impl IntoResponseParts for HxRefresh {
+    type Error = Infallible;
+
+    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        res.headers_mut().insert(
+            headers::HX_REFRESH,
+            match self.0 {
+                true => HeaderValue::from_static("true"),
+                false => HeaderValue::from_static("false"),
+            },
+        );
+        Ok(res)
+    }
+}
+
+/// The `HX-Replace-Url` header.
+///
+/// Replaces the currelt URL in the location bar.
+///
+/// Will fail if the supplied Uri contains characters that are not visible ASCII (32-127).
+#[derive(Debug, Clone)]
+pub struct HxReplaceUrl(pub Uri);
+
+impl IntoResponseParts for HxReplaceUrl {
+    type Error = HxError;
+
+    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        res.headers_mut().insert(
+            headers::HX_REPLACE_URL,
+            HeaderValue::from_maybe_shared(self.0.to_string())?,
+        );
+        Ok(res)
+    }
+}
+
+/// The `HX-Reswap` header.
+///
+/// Allows you to specidy how the response will be swapped.
+///
+/// This responder will never fail.
+#[derive(Debug, Copy, Clone)]
+pub struct HxReswap(pub SwapOption);
+
+impl IntoResponseParts for HxReswap {
+    type Error = Infallible;
+
+    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        res.headers_mut().insert(headers::HX_RESWAP, self.0.into());
+        Ok(res)
+    }
+}
+
+/// The `HX-Retarget` header.
+///
+/// A CSS selector that updates the target of the content update to a different element on the page.
+///
+/// Will fail if the supplied String contains characters that are not visible ASCII (32-127).
+#[derive(Debug, Clone)]
+pub struct HxRetarget(pub String);
+
+impl IntoResponseParts for HxRetarget {
+    type Error = HxError;
+
+    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        res.headers_mut().insert(
+            headers::HX_RETARGET,
+            HeaderValue::from_maybe_shared(self.0)?,
+        );
+        Ok(res)
+    }
+}
+
+/// The `HX-Reselect` header.
+///
+/// A CSS selector that allows you to choose which part of the response is used to be swapped in. Overrides an existing hx-select on the triggering element.
+///
+/// Will fail if the supplied String contains characters that are not visible ASCII (32-127).
+#[derive(Debug, Clone)]
+pub struct HxReselect(pub String);
+
+impl IntoResponseParts for HxReselect {
+    type Error = HxError;
+
+    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        res.headers_mut().insert(
+            headers::HX_RESELECT,
+            HeaderValue::from_maybe_shared(self.0)?,
+        );
+        Ok(res)
+    }
+}
+
+/// The `HX-Trigger` header.
+///
+/// Allows you to trigger client-side events.
+///
+/// Will fail if the supplied events contain or produce characters that are not visible ASCII (32-127) when serializing to json.
+#[derive(Debug, Clone)]
+pub struct HxResponseTrigger(pub Vec<String>);
+
+impl IntoResponseParts for HxResponseTrigger {
+    type Error = HxError;
+
+    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        res.headers_mut().insert(
+            headers::HX_TRIGGER,
+            HeaderValue::from_maybe_shared(
+                self.0
+                    .into_iter()
+                    .reduce(|acc, e| acc + ", " + &e)
+                    .unwrap_or_default(),
+            )?,
+        );
+        Ok(res)
+    }
+}
+
+/// The `HX-Trigger-After-Settle` header.
+///
+/// Allows you to trigger client-side events after the settle step.
+///
+/// Will fail if the supplied events contain or produce characters that are not visible ASCII (32-127) when serializing to json.
+#[derive(Debug, Clone)]
+pub struct HxResponseTriggerAfterSettle(pub Vec<String>);
+
+impl IntoResponseParts for HxResponseTriggerAfterSettle {
+    type Error = HxError;
+
+    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        res.headers_mut().insert(
+            headers::HX_TRIGGER_AFTER_SETTLE,
+            HeaderValue::from_maybe_shared(
+                self.0
+                    .into_iter()
+                    .reduce(|acc, e| acc + ", " + &e)
+                    .unwrap_or_default(),
+            )?,
+        );
+        Ok(res)
+    }
+}
+
+/// The `HX-Trigger-After-Swap` header.
+///
+/// Allows you to trigger client-side events after the swap step.
+///
+/// Will fail if the supplied events contain or produce characters that are not visible ASCII (32-127) when serializing to json.
+#[derive(Debug, Clone)]
+pub struct HxResponseTriggerAfterSwap(pub Vec<String>);
+
+impl IntoResponseParts for HxResponseTriggerAfterSwap {
+    type Error = HxError;
+
+    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        res.headers_mut().insert(
+            headers::HX_TRIGGER_AFTER_SWAP,
+            HeaderValue::from_maybe_shared(
+                self.0
+                    .into_iter()
+                    .reduce(|acc, e| acc + ", " + &e)
+                    .unwrap_or_default(),
+            )?,
+        );
+        Ok(res)
+    }
+}
+
+/// Values of the `hx-swap` attribute.
+// serde::Serialize is implemented in responders/serde.rs
+#[derive(Debug, Copy, Clone)]
+pub enum SwapOption {
+    /// Replace the inner html of the target element.
+    InnerHtml,
+    /// Replace the entire target element with the response.
+    OuterHtml,
+    /// Insert the response before the target element.
+    BeforeBegin,
+    /// Insert the response before the first child of the target element.
+    AfterBegin,
+    /// Insert the response after the last child of the target element
+    BeforeEnd,
+    /// Insert the response after the target element
+    AfterEnd,
+    /// Deletes the target element regardless of the response
+    Delete,
+    /// Does not append content from response (out of band items will still be processed).
+    None,
+}
+
+impl From<SwapOption> for HeaderValue {
+    fn from(value: SwapOption) -> Self {
+        match value {
+            SwapOption::InnerHtml => HeaderValue::from_static(HX_SWAP_INNER_HTML),
+            SwapOption::OuterHtml => HeaderValue::from_static(HX_SWAP_OUTER_HTML),
+            SwapOption::BeforeBegin => HeaderValue::from_static(HX_SWAP_BEFORE_BEGIN),
+            SwapOption::AfterBegin => HeaderValue::from_static(HX_SWAP_AFTER_BEGIN),
+            SwapOption::BeforeEnd => HeaderValue::from_static(HX_SWAP_BEFORE_END),
+            SwapOption::AfterEnd => HeaderValue::from_static(HX_SWAP_AFTER_END),
+            SwapOption::Delete => HeaderValue::from_static(HX_SWAP_DELETE),
+            SwapOption::None => HeaderValue::from_static(HX_SWAP_NONE),
+        }
+    }
+}
+
+pub enum HxError {
+    InvalidHeaderValue(InvalidHeaderValue),
+
+    #[cfg(feature = "serde")]
+    Serialization(serde_json::Error),
+}
+
+impl From<InvalidHeaderValue> for HxError {
+    fn from(value: InvalidHeaderValue) -> Self {
+        Self::InvalidHeaderValue(value)
+    }
+}
+
+#[cfg(feature = "serde")]
+impl From<serde_json::Error> for HxError {
+    fn from(value: serde_json::Error) -> Self {
+        Self::Serialization(value)
+    }
+}
+
+impl IntoResponse for HxError {
+    fn into_response(self) -> axum::response::Response {
+        match self {
+            Self::InvalidHeaderValue(_) => {
+                (StatusCode::INTERNAL_SERVER_ERROR, "invalid header value").into_response()
+            }
+
+            #[cfg(feature = "serde")]
+            Self::Serialization(_) => (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                "failed to serialize event",
+            )
+                .into_response(),
+        }
+    }
+}

src/responders/serde.rs

@@ -0,0 +1,205 @@
+use std::collections::HashMap;
+
+use axum::{
+    http::{HeaderValue, Uri},
+    response::{IntoResponseParts, ResponseParts},
+};
+use serde::Serialize;
+use serde_json::Value;
+
+use crate::{
+    headers,
+    responders::{
+        HX_SWAP_AFTER_BEGIN, HX_SWAP_AFTER_END, HX_SWAP_BEFORE_BEGIN, HX_SWAP_BEFORE_END,
+        HX_SWAP_DELETE, HX_SWAP_INNER_HTML, HX_SWAP_NONE, HX_SWAP_OUTER_HTML,
+    },
+    HxError, SwapOption,
+};
+
+/// The `HX-Location` header.
+///
+/// This response header can be used to trigger a client side redirection without reloading the whole page. Instead of changing the page’s location it will act like following a hx-boost link, creating a new history entry, issuing an ajax request to the value of the header and pushing the path into history.
+///
+/// Will fail if the supplied data contains or produces characters that are not visible ASCII (32-127) when serializing to json.
+#[derive(Debug, Clone, Serialize)]
+pub struct HxLocation {
+    /// Url to load the response from
+    pub path: String,
+    /// The source element of the request
+    pub source: Option<String>,
+    /// An event that "triggered" the request
+    pub event: Option<String>,
+    /// A callback that will handle the response HTML
+    pub handler: Option<String>,
+    /// The target to swap the response into
+    pub target: Option<String>,
+    /// How the response will be swapped in relative to the target
+    pub swap: Option<SwapOption>,
+    /// Values to submit with the request
+    pub values: Option<Value>,
+    /// headers to submit with the request
+    pub headers: Option<Value>,
+}
+
+impl HxLocation {
+    pub fn from_uri(uri: &Uri) -> Self {
+        Self {
+            path: uri.to_string(),
+            source: None,
+            event: None,
+            handler: None,
+            target: None,
+            swap: None,
+            values: None,
+            headers: None,
+        }
+    }
+}
+
+impl IntoResponseParts for HxLocation {
+    type Error = HxError;
+
+    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        let header_value = if self.source.is_none()
+            && self.event.is_none()
+            && self.handler.is_none()
+            && self.target.is_none()
+            && self.swap.is_none()
+            && self.values.is_none()
+            && self.headers.is_none()
+        {
+            HeaderValue::from_str(&self.path)?
+        } else {
+            HeaderValue::from_maybe_shared(serde_json::to_string(&self)?)?
+        };
+
+        res.headers_mut().insert(headers::HX_LOCATION, header_value);
+        Ok(res)
+    }
+}
+
+/// The `HX-Trigger` header.
+///
+/// Allows you to trigger client-side events.
+///
+/// Will fail if the supplied events contain or produce characters that are not visible ASCII (32-127) when serializing to json.
+#[derive(Debug, Clone)]
+pub struct HxTrigger(pub Vec<HxEvent>);
+
+impl IntoResponseParts for HxTrigger {
+    type Error = HxError;
+
+    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        res.headers_mut()
+            .insert(headers::HX_TRIGGER, events_to_header_value(self.0)?);
+        Ok(res)
+    }
+}
+
+/// The `HX-Trigger-After-Settle` header.
+///
+/// Allows you to trigger client-side events after the settle step.
+///
+/// Will fail if the supplied events contain or produce characters that are not visible ASCII (32-127) when serializing to json.
+#[derive(Debug, Clone)]
+pub struct HxTriggerAfterSettle(Vec<HxEvent>);
+
+impl IntoResponseParts for HxTriggerAfterSettle {
+    type Error = HxError;
+
+    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        res.headers_mut().insert(
+            headers::HX_TRIGGER_AFTER_SETTLE,
+            events_to_header_value(self.0)?,
+        );
+        Ok(res)
+    }
+}
+
+/// The `HX-Trigger-After-Swap` header.
+///
+/// Allows you to trigger client-side events after the swap step.
+///
+/// Will fail if the supplied events contain or produce characters that are not visible ASCII (32-127) when serializing to json.
+#[derive(Debug, Clone)]
+pub struct HxTriggerAfterSwap(Vec<HxEvent>);
+
+impl IntoResponseParts for HxTriggerAfterSwap {
+    type Error = HxError;
+
+    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        res.headers_mut().insert(
+            headers::HX_TRIGGER_AFTER_SWAP,
+            events_to_header_value(self.0)?,
+        );
+        Ok(res)
+    }
+}
+
+#[derive(Debug, Clone, Serialize)]
+pub struct HxEvent {
+    pub name: String,
+    pub data: Option<Value>,
+}
+
+impl HxEvent {
+    pub fn new<T: Serialize>(name: String) -> Self {
+        Self { name, data: None }
+    }
+    pub fn new_with_data<T: Serialize>(name: String, data: T) -> Result<Self, serde_json::Error> {
+        let data = serde_json::to_value(data)?;
+
+        Ok(Self {
+            name,
+            data: Some(data),
+        })
+    }
+}
+
+pub(crate) fn events_to_header_value(events: Vec<HxEvent>) -> Result<HeaderValue, HxError> {
+    let with_data = events.iter().any(|e| e.data.is_some());
+
+    let header_value = if with_data {
+        // at least one event contains data so the header_value needs to be json encoded.
+        let header_value = events
+            .into_iter()
+            .map(|e| (e.name, e.data.map(|d| d.to_string()).unwrap_or_default()))
+            .collect::<HashMap<_, _>>();
+        serde_json::to_string(&header_value)?
+    } else {
+        // no event contains data, the event names can be put in the header value separated
+        // by a comma.
+        events
+            .into_iter()
+            .map(|e| e.name)
+            .reduce(|acc, e| acc + ", " + &e)
+            .unwrap_or_default()
+    };
+
+    HeaderValue::from_maybe_shared(header_value).map_err(HxError::from)
+}
+
+// can be removed  and automatically derived when https://github.com/serde-rs/serde/issues/2485
+// is implemented
+impl serde::Serialize for SwapOption {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        const UNIT_NAME: &str = "SwapOption";
+        match self {
+            Self::InnerHtml => serializer.serialize_unit_variant(UNIT_NAME, 0, HX_SWAP_INNER_HTML),
+            Self::OuterHtml => serializer.serialize_unit_variant(UNIT_NAME, 1, HX_SWAP_OUTER_HTML),
+            Self::BeforeBegin => {
+                serializer.serialize_unit_variant(UNIT_NAME, 2, HX_SWAP_BEFORE_BEGIN)
+            }
+            Self::AfterBegin => {
+                serializer.serialize_unit_variant(UNIT_NAME, 3, HX_SWAP_AFTER_BEGIN)
+            }
+            Self::BeforeEnd => serializer.serialize_unit_variant(UNIT_NAME, 4, HX_SWAP_BEFORE_END),
+            Self::AfterEnd => serializer.serialize_unit_variant(UNIT_NAME, 5, HX_SWAP_AFTER_END),
+            Self::Delete => serializer.serialize_unit_variant(UNIT_NAME, 6, HX_SWAP_DELETE),
+            Self::None => serializer.serialize_unit_variant(UNIT_NAME, 7, HX_SWAP_NONE),
+        }
+    }
+}