add switch module

6 files changed, 97 insertions, 5 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 1952416..83ee38f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -577,7 +577,7 @@ checksum = "d2fabcfbdc87f4758337ca535fb41a6d701b65693ce38287d856d1674551ec9b"
 
 [[package]]
 name = "gnix"
-version = "2.0.0"
+version = "2.1.0"
 dependencies = [
  "aes-gcm-siv",
  "anyhow",
diff --git a/Cargo.toml b/Cargo.toml
index 129883f..646cad5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "gnix"
-version = "2.0.0"
+version = "2.1.0"
 edition = "2021"
 
 [dependencies]
diff --git a/readme.md b/readme.md
index 451f2dd..cef479e 100644
--- a/readme.md
+++ b/readme.md
@@ -156,6 +156,24 @@ themselves; in that case the request is passed on.
     such a form is provided with the distribution of this software, usually in
     `/usr/share/gnix/login.html` (module)
 
+- **module `switch`**
+  - Decides between two possible routes based on a condition.
+  - `condition`:
+    - `!is_websocket_upgrade`: Checks if a websocket was requested.
+    - `!is_get`: Checks if this is a GET request
+    - `!is_post`: Checks if this is a POST request
+    - `!path_starts_with <prefix>`: Checks if the URI path starts with some
+      prefix
+    - `!path_is <path>`: Checks if the URI path is exactly what you specified
+    - `!has_header <name>`: Checks if the request includes a certain header.
+  - `case_true` Handler with matched requests (module)
+  - `case_false` Handler for all other requests (module)
+
+- **module `headers`**
+  - Appends multiple headers to the response.
+  - `headers`: A map of all header name-value pairs. (object string:string)
+  - `inner`: The handler to add the headers to. (module)
+
 #### Credentials config format
 
 Login credentials for `cookie_auth` and `http_basic_auth` are supplied as either
diff --git a/src/modules/headers.rs b/src/modules/headers.rs
index b1e452e..ad4595a 100644
--- a/src/modules/headers.rs
+++ b/src/modules/headers.rs
@@ -1,4 +1,4 @@
-use super::{Node, NodeKind, NodeResponse};
+use super::{Node, NodeContext, NodeKind, NodeRequest, NodeResponse};
 use crate::{config::DynNode, error::ServiceError};
 use anyhow::Result;
 use futures::Future;
@@ -29,8 +29,8 @@ impl NodeKind for HeadersKind {
 impl Node for Headers {
     fn handle<'a>(
         &'a self,
-        context: &'a mut super::NodeContext,
-        request: super::NodeRequest,
+        context: &'a mut NodeContext,
+        request: NodeRequest,
     ) -> Pin<Box<dyn Future<Output = Result<NodeResponse, ServiceError>> + Send + Sync + 'a>> {
         Box::pin(async move {
             let mut resp = self.inner.handle(context, request).await?;
diff --git a/src/modules/mod.rs b/src/modules/mod.rs
index 2e08142..0fe9ca0 100644
--- a/src/modules/mod.rs
+++ b/src/modules/mod.rs
@@ -14,6 +14,7 @@ use hyper::{body::Incoming, Request, Response};
 use proxy::ProxyKind;
 use serde_yaml::Value;
 use std::{net::SocketAddr, pin::Pin, sync::Arc};
+use switch::SwitchKind;
 
 pub mod accesslog;
 pub mod auth;
@@ -23,6 +24,7 @@ pub mod files;
 pub mod headers;
 pub mod hosts;
 pub mod proxy;
+pub mod switch;
 
 pub type NodeRequest = Request<Incoming>;
 pub type NodeResponse = Response<BoxBody<Bytes, ServiceError>>;
@@ -37,6 +39,7 @@ pub static MODULES: &[&dyn NodeKind] = &[
     &AccessLogKind,
     &ErrorKind,
     &HeadersKind,
+    &SwitchKind,
 ];
 
 pub struct NodeContext {
diff --git a/src/modules/switch.rs b/src/modules/switch.rs
new file mode 100644
index 0000000..bbb9e98
--- /dev/null
+++ b/src/modules/switch.rs
@@ -0,0 +1,71 @@
+use super::{Node, NodeContext, NodeKind, NodeRequest, NodeResponse};
+use crate::{config::DynNode, error::ServiceError};
+use anyhow::Result;
+use futures::Future;
+use headers::{HeaderMapExt, Upgrade};
+use hyper::Method;
+use serde::Deserialize;
+use std::{pin::Pin, sync::Arc};
+
+pub struct SwitchKind;
+
+#[derive(Deserialize)]
+pub struct Switch {
+    condition: Condition,
+    case_true: DynNode,
+    case_false: DynNode,
+}
+
+impl NodeKind for SwitchKind {
+    fn name(&self) -> &'static str {
+        "switch"
+    }
+    fn instanciate(&self, config: serde_yaml::Value) -> Result<Arc<dyn Node>> {
+        Ok(Arc::new(serde_yaml::from_value::<Switch>(config)?))
+    }
+}
+
+impl Node for Switch {
+    fn handle<'a>(
+        &'a self,
+        context: &'a mut NodeContext,
+        request: NodeRequest,
+    ) -> Pin<Box<dyn Future<Output = Result<NodeResponse, ServiceError>> + Send + Sync + 'a>> {
+        Box::pin(async move {
+            let cond = self.condition.test(&request);
+            if cond {
+                &self.case_true
+            } else {
+                &self.case_false
+            }
+            .handle(context, request)
+            .await
+        })
+    }
+}
+
+#[derive(Deserialize)]
+#[serde(rename_all = "snake_case")]
+enum Condition {
+    IsWebsocketUpgrade,
+    IsPost,
+    IsGet,
+    HasHeader(String),
+    PathStartsWith(String),
+    PathIs(String),
+}
+
+impl Condition {
+    pub fn test(&self, req: &NodeRequest) -> bool {
+        match self {
+            Condition::IsWebsocketUpgrade => {
+                req.headers().typed_get::<Upgrade>() == Some(Upgrade::websocket())
+            }
+            Condition::HasHeader(name) => req.headers().contains_key(name),
+            Condition::PathStartsWith(path_prefix) => req.uri().path().starts_with(path_prefix),
+            Condition::PathIs(path) => req.uri().path() == path,
+            Condition::IsPost => req.method() == Method::POST,
+            Condition::IsGet => req.method() == Method::GET,
+        }
+    }
+}