Add a get_static_url global fn

Fix #108

CHANGELOG.md

@@ -6,6 +6,7 @@
 root page
 - Make `title` in config optional
 - Improved `gutenberg init` UX and users first experience
+- Add a `get_static_url` global function that can do cachebusting
 
 ## 0.1.1 (2017-07-16)
 

Cargo.lock

@@ -233,6 +233,7 @@ dependencies = [
 name = "config"
 version = "0.1.0"
 dependencies = [
+ "chrono 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "errors 0.1.0",
  "rendering 0.1.0",
  "serde 1.0.10 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1144,6 +1145,7 @@ name = "templates"
 version = "0.1.0"
 dependencies = [
  "base64 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "config 0.1.0",
  "content 0.1.0",
  "errors 0.1.0",
  "lazy_static 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",

README.md

@@ -64,7 +64,7 @@ the absolute URL of the current page and `current_path` that represents the path
 If you want to know all the data present in a template content, simply put `{{ __tera_context }}`
 in the templates and it will print it.
 
-Gutenberg also ships with 3 Tera global functions:
+Gutenberg also ships with a few Tera global functions:
 
 #### `get_page`
 Takes a path to a `.md` file and returns the associated page
@@ -88,6 +88,18 @@ link in markdown.
 {% set url = get_url(link="./blog/_index.md") %}
 ```
 
+#### `get_static_url`
+Gets the permalink for a given path, with cachebusting support.
+
+```jinja2
+{% get_static_url(path="path.css") %}
+```
+
+The path should start at the static folder root and should not being with a `/`. By default,
+this will add a cachebust of the format `?t=1290192` at the end of a URL. You can disable it
+by passing `cachebust=false` to the function.
+
+
 ### Static files
 Everything in the `static` folder will be copied into the output directory as-is.
 

components/config/Cargo.toml

@@ -7,6 +7,7 @@ authors = ["Vincent Prouillet <vincent@wearewizards.io>"]
 toml = "0.4"
 serde = "1.0"
 serde_derive = "1.0"
+chrono = "0.4"
 
 errors = { path = "../errors" }
 rendering = { path = "../rendering" }

components/config/src/lib.rs

@@ -4,6 +4,7 @@ extern crate toml;
 #[macro_use]
 extern crate errors;
 extern crate rendering;
+extern crate chrono;
 
 use std::collections::HashMap;
 use std::fs::File;
@@ -11,12 +12,13 @@ use std::io::prelude::*;
 use std::path::Path;
 
 use toml::{Value as Toml};
+use chrono::Utc;
 
 use errors::{Result, ResultExt};
 use rendering::highlighting::THEME_SET;
 
 
-#[derive(Debug, PartialEq, Serialize, Deserialize)]
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 pub struct Config {
     /// Base URL of the site, the only required config argument
     pub base_url: String,
@@ -48,6 +50,9 @@ pub struct Config {
 
     /// All user params set in [extra] in the config
     pub extra: Option<HashMap<String, Toml>>,
+
+    /// Set automatically when instantiating the config. Used for cachebusting
+    pub build_timestamp: Option<i64>,
 }
 
 macro_rules! set_default {
@@ -85,6 +90,7 @@ impl Config {
             None => config.highlight_theme = Some("base16-ocean-dark".to_string())
         };
 
+        config.build_timestamp = Some(Utc::now().timestamp());
         Ok(config)
     }
 
@@ -136,6 +142,7 @@ impl Default for Config {
             insert_anchor_links: Some(false),
             compile_sass: Some(false),
             extra: None,
+            build_timestamp: Some(1),
         }
     }
 }

components/site/src/lib.rs

@@ -218,6 +218,7 @@ impl Site {
 
         self.tera.register_global_function("get_page", global_fns::make_get_page(&self.pages));
         self.tera.register_global_function("get_section", global_fns::make_get_section(&self.sections));
+        self.tera.register_global_function("get_static_url", global_fns::make_get_static_url(self.config.clone()));
         self.register_get_url_fn();
 
         Ok(())

components/templates/Cargo.toml

@@ -12,3 +12,4 @@ pulldown-cmark = "0"
 errors = { path = "../errors" }
 utils = { path = "../utils" }
 content = { path = "../content" }
+config = { path = "../config" }

components/templates/src/global_fns.rs

@@ -4,6 +4,7 @@ use std::path::{PathBuf};
 use tera::{GlobalFn, Value, from_value, to_value, Result};
 
 use content::{Page, Section};
+use config::Config;
 use utils::site::resolve_internal_link;
 
 
@@ -51,7 +52,7 @@ pub fn make_get_section(all_sections: &HashMap<PathBuf, Section>) -> GlobalFn {
     })
 }
 
-pub fn make_get_url(permalinks: HashMap<String, String>,) -> GlobalFn {
+pub fn make_get_url(permalinks: HashMap<String, String>) -> GlobalFn {
     Box::new(move |args| -> Result<Value> {
         match args.get("link") {
             Some(val) => match from_value::<String>(val.clone()) {
@@ -65,3 +66,59 @@ pub fn make_get_url(permalinks: HashMap<String, String>,) -> GlobalFn {
         }
     })
 }
+
+pub fn make_get_static_url(config: Config) -> GlobalFn {
+    Box::new(move |args| -> Result<Value> {
+        let cachebust = args
+            .get("cachebust")
+            .map_or(true, |c| {
+                from_value::<bool>(c.clone()).unwrap_or(true)
+            });
+
+        match args.get("path") {
+            Some(val) => match from_value::<String>(val.clone()) {
+                Ok(v) => {
+                    let mut permalink = config.make_permalink(&v);
+                    if cachebust {
+                        permalink = format!("{}?t={}", permalink, config.build_timestamp.unwrap());
+                    }
+                    Ok(to_value(permalink).unwrap())
+                },
+                Err(_) => Err(format!("`get_static_url` received path={:?} but it requires a string", val).into()),
+
+            },
+            None => Err("`get_static_url` requires a `path` argument.".into()),
+        }
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::make_get_static_url;
+
+    use std::collections::HashMap;
+
+    use tera::to_value;
+
+    use config::Config;
+
+
+    #[test]
+    fn add_cachebust_to_static_url_by_default() {
+        let config = Config::default();
+        let static_fn = make_get_static_url(config);
+        let mut args = HashMap::new();
+        args.insert("path".to_string(), to_value("app.css").unwrap());
+        assert_eq!(static_fn(args).unwrap(), "http://a-website.com/app.css/?t=1");
+    }
+
+    #[test]
+    fn can_disable_cachebust_for_static_url() {
+        let config = Config::default();
+        let static_fn = make_get_static_url(config);
+        let mut args = HashMap::new();
+        args.insert("path".to_string(), to_value("app.css").unwrap());
+        args.insert("cachebust".to_string(), to_value(false).unwrap());
+        assert_eq!(static_fn(args).unwrap(), "http://a-website.com/app.css/");
+    }
+}

components/templates/src/lib.rs

@@ -8,6 +8,7 @@ extern crate pulldown_cmark;
 extern crate errors;
 extern crate utils;
 extern crate content;
+extern crate config;
 
 pub mod filters;
 pub mod global_fns;