simplify fetch_source logic

src/filter.rs

@@ -50,6 +50,9 @@ pub struct FilterContext {
   /// from a relative path.
   base: Option<Url>,
 
+  /// User supplied source (`?source=` query parameter)
+  source: Option<Url>,
+
   /// The maximum number of filters to run on this pipeline
   filter_skip: Option<FilterSkip>,
 
@@ -63,6 +66,7 @@ impl FilterContext {
     Self {
       base: None,
       filter_skip: None,
+      source: None,
       extra_queries: HashMap::new(),
     }
   }
@@ -79,6 +83,10 @@ impl FilterContext {
     &self.extra_queries
   }
 
+  pub fn source(&self) -> Option<&Url> {
+    self.source.as_ref()
+  }
+
   pub fn set_filter_skip(&mut self, filter_skip: FilterSkip) {
     self.filter_skip = Some(filter_skip);
   }
@@ -90,6 +98,7 @@ impl FilterContext {
   pub fn subcontext(&self) -> Self {
     Self {
       base: self.base.clone(),
+      source: None,
       filter_skip: None,
       extra_queries: self.extra_queries.clone(),
     }
@@ -98,6 +107,7 @@ impl FilterContext {
   pub fn from_param(param: &crate::server::EndpointParam) -> Self {
     Self {
       base: param.base().cloned(),
+      source: param.source().cloned(),
       filter_skip: param.filter_skip().cloned(),
       extra_queries: param.extra_queries().clone(),
     }

src/server/endpoint.rs

@@ -279,7 +279,6 @@ impl EndpointService {
   }
 
   pub async fn run(self, param: EndpointParam) -> Result<Feed> {
-    let source = self.find_source(&param.source)?;
     let mut context = FilterContext::from_param(&param);
     let feed = source
       .fetch_feed(&context, Some(&self.client))
@@ -311,18 +310,6 @@ impl EndpointService {
     Ok(feed)
   }
 
-  fn find_source(&self, param: &Option<Url>) -> Result<Source> {
-    match &self.source {
-      Source::Dynamic => param
-        .as_ref()
-        .ok_or(Error::Message("missing source".into()))
-        .cloned()
-        .map(Source::from),
-      // ignore the source from param if it's already specified in config
-      source => Ok(source.clone()),
-    }
-  }
-
   pub fn config_changed(&self, config: &EndpointServiceConfig) -> bool {
     self.config != *config
   }

src/source.rs

@@ -258,30 +258,24 @@ impl Source {
     context: &FilterContext,
     client: Option<&Client>,
   ) -> Result<Feed> {
-    if let Source::FromScratch(config) = self {
-      let feed = Feed::from(config);
-      return Ok(feed);
-    }
-
-    if let Source::Templated(config) = self {
-      let source = config.to_regular_source(context.extra_queries())?;
-      return Box::pin(source.fetch_feed(context, client)).await;
-    }
+    let client = client.ok_or_else(|| Error::Message("client not set".into()));
 
-    let source_url = match self {
-      Source::AbsoluteUrl(url) => url.clone(),
+    match self {
+      Source::Dynamic => {
+        let url = context.source().ok_or(Error::DynamicSourceUnspecified)?;
+        client?.fetch_feed(url).await
+      }
+      Source::AbsoluteUrl(url) => client?.fetch_feed(url).await,
       Source::RelativeUrl(path) => {
-        let base = context.base_expected()?;
-        base.join(path)?
+        let url = context.base_expected()?.join(path)?;
+        client?.fetch_feed(&url).await
       }
-      Source::Templated(_) | Source::FromScratch(_) | Source::Dynamic => {
-        unreachable!()
+      Source::FromScratch(config) => Ok(Feed::from(config)),
+      Source::Templated(template) => {
+        let source = template.to_regular_source(context.extra_queries())?;
+        Box::pin(source.fetch_feed(context, client.ok())).await
       }
-    };
-
-    let client =
-      client.ok_or_else(|| Error::Message("client not set".into()))?;
-    client.fetch_feed(&source_url).await
+    }
   }
 }
 

src/util.rs

@@ -125,6 +125,9 @@ pub enum Error {
   #[error("Failed fetching source: {0}")]
   FetchSource(Box<Error>),
 
+  #[error("Dynamic source unspecified")]
+  DynamicSourceUnspecified,
+
   #[error("Source parameter {placeholder} failed to match validation: {validation} (input: {input})")]
   SourceTemplateValidation {
     placeholder: String,