[pbs-devel] [PATCH proxmox-backup 4/6] server/config: add ability to get mtime of files for template

[Dominik Csapak]

this will help us to circumvent browser caching issues, by
giving the server config a list of files that it will stat for their mtime
which we can the use in the template to append a "GET" parameter
(this lets the browser refresh the resource if the parameter is different)

Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
---
 src/bin/proxmox-backup-proxy.rs |  4 +--
 src/server/config.rs            | 55 +++++++++++++++++++++++----------
 src/server/rest.rs              |  2 +-
 3 files changed, 41 insertions(+), 20 deletions(-)

diff --git a/src/bin/proxmox-backup-proxy.rs b/src/bin/proxmox-backup-proxy.rs
index 3f07db89..d4425adc 100644
--- a/src/bin/proxmox-backup-proxy.rs
+++ b/src/bin/proxmox-backup-proxy.rs
@@ -94,8 +94,8 @@ async fn run() -> Result<(), Error> {
 
     let mut indexpath = PathBuf::from(buildcfg::JS_DIR);
     indexpath.push("index.hbs");
-    config.register_template("index", &indexpath)?;
-    config.register_template("console", "/usr/share/pve-xtermjs/index.html.hbs")?;
+    config.register_template("index", &indexpath, &[])?;
+    config.register_template("console", "/usr/share/pve-xtermjs/index.html.hbs", &[])?;
 
     let mut commando_sock = server::CommandoSocket::new(server::our_ctrl_sock());
 
diff --git a/src/server/config.rs b/src/server/config.rs
index c7300668..846725a3 100644
--- a/src/server/config.rs
+++ b/src/server/config.rs
@@ -7,12 +7,12 @@ use std::sync::{Arc, Mutex, RwLock};
 use anyhow::{bail, Error, format_err};
 use hyper::Method;
 use handlebars::Handlebars;
-use serde::Serialize;
+use serde_json::{Value, json};
 
 use proxmox::api::{ApiMethod, Router, RpcEnvironmentType};
 use proxmox::tools::fs::{create_path, CreateOptions};
 
-use crate::tools::{FileLogger, FileLogOptions};
+use crate::tools::{FileLogger, FileLogOptions, self};
 
 pub struct ApiConfig {
     basedir: PathBuf,
@@ -20,7 +20,7 @@ pub struct ApiConfig {
     aliases: HashMap<String, PathBuf>,
     env_type: RpcEnvironmentType,
     templates: RwLock<Handlebars<'static>>,
-    template_files: RwLock<HashMap<String, (SystemTime, PathBuf)>>,
+    template_files: RwLock<HashMap<String, (SystemTime, PathBuf, Vec<PathBuf>)>>,
     request_log: Option<Arc<Mutex<FileLogger>>>,
 }
 
@@ -76,7 +76,7 @@ impl ApiConfig {
         self.env_type
     }
 
-    pub fn register_template<P>(&self, name: &str, path: P) -> Result<(), Error>
+    pub fn register_template<P>(&self, name: &str, path: P, files_to_check: &[&str]) -> Result<(), Error>
     where
         P: Into<PathBuf>
     {
@@ -85,42 +85,63 @@ impl ApiConfig {
         }
 
         let path: PathBuf = path.into();
-        let metadata = metadata(&path)?;
-        let mtime = metadata.modified()?;
+        let mtime = metadata(&path)?.modified()?;
+
+        let mut files = Vec::new();
+
+        for file in files_to_check {
+            let (_, components) = crate::tools::normalize_uri_path(file)?;
+            let path = self.find_alias(&components);
+            if path.file_name().is_none() {
+                bail!("error registering template: has no filename: {:?}", file);
+            }
+            files.push(path);
+        }
 
         self.templates.write().unwrap().register_template_file(name, &path)?;
-        self.template_files.write().unwrap().insert(name.to_string(), (mtime, path));
+        self.template_files.write().unwrap().insert(name.to_string(), (mtime, path, files));
 
         Ok(())
     }
 
     /// Checks if the template was modified since the last rendering
     /// if yes, it loads a the new version of the template
-    pub fn render_template<T>(&self, name: &str, data: &T) -> Result<String, Error>
-    where
-        T: Serialize,
+    pub fn render_template(&self, name: &str, mut data: Value) -> Result<String, Error>
     {
-        let path;
+        fn get_timestamps(files: &Vec<PathBuf>) -> Value {
+            let mut value = json!({});
+
+            for file in files {
+                let mtime = tools::fs::get_file_mtime(file).unwrap_or_else(|_| 0);
+                let filename = file.file_name().unwrap().to_string_lossy();
+                value[filename.into_owned()] = Value::from(mtime);
+            }
+            value
+        }
+
         let mtime;
         {
             let template_files = self.template_files.read().unwrap();
-            let (old_mtime, old_path) = template_files.get(name).ok_or_else(|| format_err!("template not found"))?;
+            let (old_mtime, old_path, files) = template_files.get(name).ok_or_else(|| format_err!("template not found"))?;
 
             mtime = metadata(old_path)?.modified()?;
             if mtime <= *old_mtime {
-                return self.templates.read().unwrap().render(name, data).map_err(|err| format_err!("{}", err));
+                data["times".to_string()] = get_timestamps(files);
+                return self.templates.read().unwrap().render(name, &data).map_err(|err| format_err!("{}", err));
             }
-            path = old_path.to_path_buf();
         }
 
         {
             let mut template_files = self.template_files.write().unwrap();
             let mut templates = self.templates.write().unwrap();
 
-            templates.register_template_file(name, &path)?;
-            template_files.insert(name.to_string(), (mtime, path));
+            let (time, path, files) = template_files.get_mut(name).ok_or_else(|| format_err!("template not found"))?;
+
+            templates.register_template_file(name, path)?;
+            *time = mtime;
 
-            templates.render(name, data).map_err(|err| format_err!("{}", err))
+            data["times".to_string()] = get_timestamps(files);
+            templates.render(name, &data).map_err(|err| format_err!("{}", err))
         }
     }
 
diff --git a/src/server/rest.rs b/src/server/rest.rs
index d0169ba5..fa01522d 100644
--- a/src/server/rest.rs
+++ b/src/server/rest.rs
@@ -437,7 +437,7 @@ fn get_index(
         "debug": debug,
     });
 
-    let (ct, index) = match api.render_template(template_file, &data) {
+    let (ct, index) = match api.render_template(template_file, data) {
         Ok(index) => ("text/html", index),
         Err(err) => {
             ("text/plain", format!("Error rendering template: {}", err))
-- 
2.20.1