Use Figment's 'Value' in contrib templating.

Previously, 'serde_json::Value' was used to store the serialized
template context. This value does not represent all of serde's data
model. This means we may fail to serialize a valid Rust value into it,
for instance, 128-bit integers. This is reduced with Figment's 'Value',
which supports the majority if not all of the serde data model.

At present, all supported templating engines use 'serde_json::Value', so
in practice, this commit has no effect but to reduce local dependencies
and provide better error messages for bad contexts.

contrib/dyn_templates/Cargo.toml

@@ -16,8 +16,6 @@ tera = ["tera_"]
 handlebars = ["handlebars_"]
 
 [dependencies]
-serde = "1.0"
-serde_json = "1.0.26"
 glob = "0.3"
 notify = "4.0.6"
 normpath = "0.3"

contrib/dyn_templates/src/engine.rs

@@ -1,7 +1,7 @@
 use std::path::Path;
 use std::collections::HashMap;
 
-use serde::Serialize;
+use rocket::serde::Serialize;
 
 use crate::TemplateInfo;
 

contrib/dyn_templates/src/handlebars_templates.rs

@@ -1,6 +1,6 @@
 use std::path::Path;
 
-use serde::Serialize;
+use rocket::serde::Serialize;
 
 use crate::engine::Engine;
 pub use crate::handlebars::Handlebars;
@@ -29,12 +29,8 @@ impl Engine for Handlebars<'static> {
             return None;
         }
 
-        match Handlebars::render(self, name, &context) {
+        Handlebars::render(self, name, &context)
-            Ok(string) => Some(string),
+            .map_err(|e| error_!("Handlebars: {}", e))
-            Err(e) => {
+            .ok()
-                error_!("Error rendering Handlebars template '{}': {}", name, e);
-                None
-            }
-        }
     }
 }

contrib/dyn_templates/src/lib.rs

@@ -118,8 +118,8 @@
 //!
 //! Templates are rendered with the `render` method. The method takes in the
 //! name of a template and a context to render the template with. The context
-//! can be any type that implements [`Serialize`] from [`serde`] and would
+//! can be any type that implements [`Serialize`] and would serialize to an
-//! serialize to an `Object` value.
+//! `Object` value.
 //!
 //! ## Automatic Reloading
 //!
@@ -127,8 +127,6 @@
 //! will be automatically reloaded from disk if any changes have been made to
 //! the templates directory since the previous request. In release builds,
 //! template reloading is disabled to improve performance and cannot be enabled.
-//!
-//! [`Serialize`]: serde::Serialize
 
 #![doc(html_root_url = "https://api.rocket.rs/v0.5-rc/rocket_dyn_templates")]
 #![doc(html_favicon_url = "https://rocket.rs/images/favicon.ico")]
@@ -166,18 +164,16 @@ pub use self::metadata::Metadata;
 use self::fairing::TemplateFairing;
 use self::context::{Context, ContextManager};
 
-use serde::Serialize;
-use serde_json::{Value, to_value};
-
 use std::borrow::Cow;
 use std::path::PathBuf;
-use std::error::Error;
 
 use rocket::{Rocket, Orbit, Ignite, Sentinel};
 use rocket::request::Request;
 use rocket::fairing::Fairing;
 use rocket::response::{self, Responder};
 use rocket::http::{ContentType, Status};
+use rocket::figment::{value::Value, error::Error};
+use rocket::serde::Serialize;
 
 const DEFAULT_TEMPLATE_DIR: &str = "templates";
 
@@ -191,7 +187,7 @@ const DEFAULT_TEMPLATE_DIR: &str = "templates";
 #[derive(Debug)]
 pub struct Template {
     name: Cow<'static, str>,
-    value: Option<Value>
+    value: Result<Value, Error>
 }
 
 #[derive(Debug)]
@@ -299,7 +295,7 @@ impl Template {
     /// }
     /// ```
     pub fn try_custom<F: Send + Sync + 'static>(f: F) -> impl Fairing
-        where F: Fn(&mut Engines) -> Result<(), Box<dyn Error>>
+        where F: Fn(&mut Engines) -> Result<(), Box<dyn std::error::Error>>
     {
         TemplateFairing { callback: Box::new(f) }
     }
@@ -325,7 +321,7 @@ impl Template {
     pub fn render<S, C>(name: S, context: C) -> Template
         where S: Into<Cow<'static, str>>, C: Serialize
     {
-        Template { name: name.into(), value: to_value(context).ok() }
+        Template { name: name.into(), value: Value::serialize(context) }
     }
 
     /// Render the template named `name` with the context `context` into a
@@ -386,13 +382,13 @@ impl Template {
         let info = ctxt.templates.get(name).ok_or_else(|| {
             let ts: Vec<_> = ctxt.templates.keys().map(|s| s.as_str()).collect();
             error_!("Template '{}' does not exist.", name);
-            info_!("Known templates: {}", ts.join(", "));
+            info_!("Known templates: {}.", ts.join(", "));
             info_!("Searched in {:?}.", ctxt.root);
             Status::InternalServerError
         })?;
 
-        let value = self.value.ok_or_else(|| {
+        let value = self.value.map_err(|e| {
-            error_!("The provided template context failed to serialize.");
+            error_!("Template context failed to serialize: {}.", e);
             Status::InternalServerError
         })?;
 

contrib/dyn_templates/src/tera_templates.rs

@@ -1,7 +1,7 @@
 use std::path::Path;
 use std::error::Error;
 
-use serde::Serialize;
+use rocket::serde::Serialize;
 
 use crate::engine::Engine;
 
@@ -42,16 +42,9 @@ impl Engine for Tera {
             return None;
         };
 
-        let tera_ctx = match Context::from_serialize(context) {
+        let tera_ctx = Context::from_serialize(context)
-            Ok(ctx) => ctx,
+            .map_err(|e| error_!("Tera context error: {}.", e))
-            Err(_) => {
+            .ok()?;
-                error_!(
-                    "Error generating context when rendering Tera template '{}'.",
-                    name
-                );
-                return None;
-            }
-        };
 
         match Tera::render(self, name, &tera_ctx) {
             Ok(string) => Some(string),

contrib/dyn_templates/tests/templates.rs

@@ -126,6 +126,21 @@ mod tera_tests {
         assert_eq!(template, Some(ESCAPED_EXPECTED.into()));
     }
 
+    // u128 is not supported. enable when it is.
+    // #[test]
+    // fn test_tera_u128() {
+    //     const EXPECTED: &'static str
+    //         = "\nh_start\ntitle: 123\nh_end\n\n\n1208925819614629174706176\n\nfoot\n";
+    //
+    //     let client = Client::debug(rocket()).unwrap();
+    //     let mut map = HashMap::new();
+    //     map.insert("title", 123);
+    //     map.insert("number", 1u128 << 80);
+    //
+    //     let template = Template::show(client.rocket(), "tera/txt_test", &map);
+    //     assert_eq!(template, Some(EXPECTED.into()));
+    // }
+
     #[test]
     fn test_template_metadata_with_tera() {
         let client = Client::debug(rocket()).unwrap();
@@ -151,11 +166,11 @@ mod handlebars_tests {
     use rocket::http::Status;
     use rocket::local::blocking::Client;
 
+    #[test]
+    fn test_handlebars_templates() {
         const EXPECTED: &'static str
             = "Hello _test_!\n\n<main> &lt;script /&gt; hi </main>\nDone.\n\n";
 
-    #[test]
-    fn test_handlebars_templates() {
         let client = Client::debug(rocket()).unwrap();
         let mut map = HashMap::new();
         map.insert("title", "_test_");
@@ -166,6 +181,21 @@ mod handlebars_tests {
         assert_eq!(template, Some(EXPECTED.into()));
     }
 
+    // u128 is not supported. enable when it is.
+    // #[test]
+    // fn test_handlebars_u128() {
+    //     const EXPECTED: &'static str
+    //         = "Hello 123!\n\n<main> 1208925819614629174706176 </main>\nDone.\n\n";
+    //
+    //     let client = Client::debug(rocket()).unwrap();
+    //     let mut map = HashMap::new();
+    //     map.insert("title", 123);
+    //     map.insert("number", 1u128 << 80);
+    //
+    //     let template = Template::show(client.rocket(), "hbs/test", &map);
+    //     assert_eq!(template, Some(EXPECTED.into()));
+    // }
+
     #[test]
     fn test_template_metadata_with_handlebars() {
         let client = Client::debug(rocket()).unwrap();