Determine Content-Type during compilation

3 files changed, 22 insertions, 0 deletions

diff --git a/askama/src/lib.rs b/askama/src/lib.rs
index f1aa91c..ccfddc8 100644
--- a/askama/src/lib.rs
+++ b/askama/src/lib.rs
@@ -86,6 +86,9 @@ pub trait Template {
 
     /// Provides a conservative estimate of the expanded length of the rendered template
     const SIZE_HINT: usize;
+
+    /// The MIME type (Content-Type) of the data that gets rendered by this Template
+    const MIME_TYPE: &'static str;
 }
 
 /// Object-safe wrapper trait around [`Template`] implementers
@@ -103,6 +106,9 @@ pub trait DynTemplate {
 
     /// Provides a conservative estimate of the expanded length of the rendered template
     fn size_hint(&self) -> usize;
+
+    /// The MIME type (Content-Type) of the data that gets rendered by this Template
+    fn mime_type(&self) -> &'static str;
 }
 
 impl<T: Template> DynTemplate for T {
@@ -121,6 +127,10 @@ impl<T: Template> DynTemplate for T {
     fn size_hint(&self) -> usize {
         Self::SIZE_HINT
     }
+
+    fn mime_type(&self) -> &'static str {
+        Self::MIME_TYPE
+    }
 }
 
 pub use crate::shared::filters;
@@ -162,6 +172,8 @@ mod tests {
             const EXTENSION: Option<&'static str> = Some("txt");
 
             const SIZE_HINT: usize = 4;
+
+            const MIME_TYPE: &'static str = "text/plain; charset=utf-8";
         }
 
         fn render(t: &dyn DynTemplate) -> String {
diff --git a/askama_shared/src/generator.rs b/askama_shared/src/generator.rs
index 5c6303c..cd18819 100644
--- a/askama_shared/src/generator.rs
+++ b/askama_shared/src/generator.rs
@@ -165,6 +165,10 @@ impl<'a, S: std::hash::BuildHasher> Generator<'a, S> {
         buf.writeln(&format!("{}", size_hint))?;
         buf.writeln(";")?;
 
+        buf.writeln("const MIME_TYPE: &'static ::std::primitive::str = ")?;
+        buf.writeln(&format!("{:?}", &self.input.mime_type))?;
+        buf.writeln(";")?;
+
         buf.writeln("}")?;
         Ok(())
     }
diff --git a/askama_shared/src/input.rs b/askama_shared/src/input.rs
index a679461..17410ed 100644
--- a/askama_shared/src/input.rs
+++ b/askama_shared/src/input.rs
@@ -14,6 +14,7 @@ pub struct TemplateInput<'a> {
     pub print: Print,
     pub escaper: &'a str,
     pub ext: Option<String>,
+    pub mime_type: String,
     pub parent: Option<&'a syn::Type>,
     pub path: PathBuf,
 }
@@ -180,6 +181,10 @@ impl TemplateInput<'_> {
             CompileError::String(format!("no escaper defined for extension '{}'", escaping,))
         })?;
 
+        let mime_type =
+            extension_to_mime_type(ext_default_to_path(ext.as_deref(), &path).unwrap_or("txt"))
+                .to_string();
+
         Ok(TemplateInput {
             ast,
             config,
@@ -188,6 +193,7 @@ impl TemplateInput<'_> {
             print,
             escaper,
             ext,
+            mime_type,
             parent,
             path,
         })