feat: add csv_attachment component

examples/todo application (PostgreSQL)/csv_attachment.sql

@@ -0,0 +1,6 @@
+select 
+    'csv_attachment' as component, 
+    ';' as separator, 
+    'todo.csv' as filename;
+
+select * from todos;

examples/todo application (PostgreSQL)/index.sql

@@ -17,4 +17,8 @@ select
     'todo_form.sql'     as link,
     'green' as color,
     'Add new todo'  as title,
-    'circle-plus'  as icon;
+    'circle-plus'  as icon;
+select 
+    '/csv_attachment.sql' as link,
+    'Download'  as title,
+    'download' as icon;

sqlpage/templates/csv_attachment.handlebars

@@ -0,0 +1,6 @@
+{{#each_row}}
+{{#if (eq @row_index 0)}}
+{{#each this}}{{@key}}{{#unless @last}}{{default ../../separator ","}}{{/unless}}{{/each}}{{../linebreak}}
+{{/if}}
+{{#each this}}{{this}}{{#unless @last}}{{default ../../separator ","}}{{/unless}}{{/each}}{{../linebreak}}
+{{/each_row}}

src/render.rs

@@ -60,6 +60,7 @@ impl<'a, W: std::io::Write> HeaderContext<W> {
             Some("http_header") => self.add_http_header(&data).map(PageContext::Header),
             Some("redirect") => self.redirect(&data).map(PageContext::Close),
             Some("json") => self.json(&data).map(PageContext::Close),
+            Some("csv_attachment") => self.csv_attachment(data).await,
             Some("cookie") => self.add_cookie(&data).map(PageContext::Header),
             Some("authentication") => self.authentication(data).await,
             _ => self.start_body(data).await,
@@ -201,6 +202,25 @@ impl<'a, W: std::io::Write> HeaderContext<W> {
         Ok(self.response.body(json_response))
     }
 
+    async fn csv_attachment(mut self, data: JsonValue) -> anyhow::Result<PageContext<W>> {
+        let filename = data
+            .get("filename")
+            .and_then(JsonValue::as_str)
+            .unwrap_or("output.csv");
+
+        self.response
+            .insert_header((header::CONTENT_TYPE, "text/csv"))
+            .insert_header((
+                header::CONTENT_DISPOSITION,
+                format!("attachment; filename=\"{}\"", filename),
+            ));
+
+        self.request_context.is_embedded = true;
+        let page_content = self.start_body(data).await?;
+
+        Ok(page_content)
+    }
+
     async fn authentication(mut self, mut data: JsonValue) -> anyhow::Result<PageContext<W>> {
         let password_hash = take_object_str(&mut data, "password_hash");
         let password = take_object_str(&mut data, "password");