Adds Observed trait for checking an object is modified (#53)

* Adds Observed trait for checking an object is modified, impl in Content

src/content/mod.rs

@@ -1,10 +1,11 @@
 use std::cmp::min;
+use std::time::SystemTime;
 
 use serde::{Deserialize, Serialize};
 
-use crate::filesystem::file::File;
-use crate::filesystem::file::{read_file_bytes, read_file_utf8, write_file_bytes, FileNotReadError};
-use crate::util::dump_bytes;
+use crate::filesystem::file::{file_hash, File, Observed};
+use crate::filesystem::file::{read_file_bytes, read_file_utf8, write_file_bytes, FileError};
+use crate::util::{dump_bytes, hash};
 
 use self::mime_type::infer_mime_type;
 
@@ -23,14 +24,28 @@ pub mod mime_type;
 /// 
 /// - The body is unpopulated until [Content::load_from_file] is called
 /// - The body may be converted to a utf8 string using [Content::utf8_body]
-#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct Content
 {
     uri: String,
     body: Vec<u8>,
     content_type: String,
     disk_path: String,
-    cache_period_seconds: u16
+    cache_period_seconds: u16,
+    hash: Vec<u8>,
+    last_refreshed: SystemTime
+}
+
+impl PartialEq for Content
+{
+    fn eq(&self, other: &Content) -> bool
+    {
+        return self.uri == other.uri && self.body == other.body &&
+               self.content_type == other.content_type &&
+               self.disk_path == other.disk_path &&
+               self.cache_period_seconds == other.cache_period_seconds &&
+               self.hash == other.hash
+    }
 }
 
 impl File for Content
@@ -51,6 +66,24 @@ impl File for Content
     }
 }
 
+impl Observed for Content
+{
+    fn is_stale(&self) -> bool
+    {
+        // this is 4x slower than using the modified date
+        //  but the modified date fails when is_stale is called
+        //  very soon after creation/modification, plus may
+        //  not be guaranteed cross platform, this is.
+        //  We can check 100,000 files in 447 millis
+        return file_hash(&self.disk_path) != self.hash
+    }
+
+    fn refresh(&mut self)
+    {
+        let _ = self.load_from_file();
+    }
+}
+
 impl Content
 {
     pub fn new(uri: &str, disk_path: &str, cache: u16) -> Content
@@ -61,18 +94,26 @@ impl Content
             body: vec![], 
             disk_path: disk_path.to_string(), 
             content_type: infer_mime_type(disk_path).to_string(),
-            cache_period_seconds: cache 
+            cache_period_seconds: cache,
+            hash: vec![],
+            last_refreshed: SystemTime::now()
         }
     }
 
-    pub fn load_from_file(&mut self) -> Result<(), FileNotReadError>
+    pub fn load_from_file(&mut self) -> Result<(), FileError>
     {
         match self.read_bytes()
         {
-            Some(data) => {self.body = data; Ok(())}
+            Some(data) => 
+            {
+                self.body = data.clone();
+                self.hash = hash(data);
+                self.last_refreshed = SystemTime::now();
+                Ok(())
+            }
             None => 
             {
-                Err(FileNotReadError { why: format!("Could not read bytes from {}", self.disk_path)})
+                Err(FileError { why: format!("Could not read bytes from {}", self.disk_path)})
             }
         }
     }

src/content/pages/page.rs

@@ -2,7 +2,7 @@ use axum::response::{IntoResponse, Response, Html};
 use regex::Regex;
 use serde::{Deserialize, Serialize};
 
-use crate::{content::Content, filesystem::file::{File, FileNotReadError}};
+use crate::{content::Content, filesystem::file::{File, FileError}};
 
 /// An HTML webpage
 /// 
@@ -48,7 +48,7 @@ impl Page
         }
     }
 
-    pub fn load_from_file(&mut self) -> Result<(), FileNotReadError>
+    pub fn load_from_file(&mut self) -> Result<(), FileError>
     {
         self.content.load_from_file()
     }

src/content/resources/resource.rs

@@ -1,7 +1,7 @@
 use axum::response::{Html, IntoResponse, Response};
 use serde::{Serialize, Deserialize};
 
-use crate::{content::Content, filesystem::file::FileNotReadError};
+use crate::{content::Content, filesystem::file::FileError};
 
 /// A non-HTML resource
 /// 
@@ -43,7 +43,7 @@ impl Resource
         }
     }
 
-    pub fn load_from_file(&mut self) -> Result<(), FileNotReadError>
+    pub fn load_from_file(&mut self) -> Result<(), FileError>
     {
         self.content.load_from_file()
     }

src/filesystem/file.rs

@@ -1,12 +1,14 @@
 use std::{fmt, fs, io::{Read, Write}};
 
+use crate::util::hash;
+
 #[derive(Debug, Clone)]
-pub struct FileNotReadError
+pub struct FileError
 {
     pub why: String
 }
 
-impl fmt::Display for FileNotReadError {
+impl fmt::Display for FileError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "{}", self.why)
     }
@@ -20,6 +22,12 @@ pub trait File
     fn read_utf8(&self) -> Option<String>;
 }
 
+pub trait Observed
+{
+    fn is_stale(&self) -> bool;
+    fn refresh(&mut self);
+}
+
 pub fn write_file_bytes(path: &str, data: &[u8])
 {
     let mut file = fs::File::create(path).unwrap();
@@ -68,4 +76,13 @@ pub fn read_file_bytes(path: &str) -> Option<Vec<u8>>
         },
         Ok(_) => Some(s)
     }
+}
+
+pub fn file_hash(path: &str) -> Vec<u8>
+{
+    match read_file_bytes(path)
+    {
+        Some(d) => hash(d),
+        None => vec![]
+    }
 }

src/filesystem/observed.rs

@@ -0,0 +1,5 @@
+pub trait Observed
+{
+    fn stale(&self) -> bool;
+    fn refresh(&mut self);
+}

src/util.rs

@@ -1,6 +1,7 @@
 use core::fmt;
 use std::{fmt::Write, io::{Read, Write as ioWrite}};
 use libflate::deflate::{Encoder, Decoder};
+use openssl::sha::Sha256;
 use regex::Regex;
 
 pub fn dump_bytes(v: &[u8]) -> String 
@@ -86,20 +87,34 @@ pub fn compress(bytes: &[u8]) -> Result<Vec<u8>, CompressionError>
     }
 }
 
-pub fn decompress(bytes: Vec<u8>) -> Result<String, CompressionError>
+pub fn decompress(bytes: Vec<u8>) -> Result<Vec<u8>, CompressionError>
 {
     let mut decoder = Decoder::new(&bytes[..]);
     let mut decoded_data = Vec::new();
 
     match decoder.read_to_end(&mut decoded_data)
     {
-        Ok(_) => (),
+        Ok(_) => Ok(decoded_data),
         Err(e) => 
         {
-            return Err(CompressionError { why: format!("Error decoding data: {}", e) })
+            Err(CompressionError { why: format!("Error decoding data: {}", e) })
         }
     }
-
+}
+
+pub fn compress_string(s: &String) -> Result<Vec<u8>, CompressionError>
+{
+    compress(s.as_bytes())
+}
+
+pub fn decompress_utf8_string(compressed: Vec<u8>) -> Result<String, CompressionError>
+{
+    let decoded_data = match decompress(compressed)
+    {
+        Ok(d) => d,
+        Err(e) => return Err(e)
+    };
+
     match std::str::from_utf8(&decoded_data)
     {
         Ok(s) => Ok(s.to_string()),
@@ -109,3 +124,10 @@ pub fn decompress(bytes: Vec<u8>) -> Result<String, CompressionError>
         }
     }
 }
+
+pub fn hash(v: Vec<u8>) -> Vec<u8>
+{
+    let mut sha = Sha256::new();
+    sha.update(&v);
+    sha.finish().to_vec()
+}

tests/test_content.rs

@@ -0,0 +1,59 @@
+mod common;
+
+#[cfg(test)]
+mod test_content
+{
+    use std::{fs::remove_file, path::Path};
+
+    use busser::{content::Content, filesystem::file::{file_hash, write_file_bytes, Observed}, util::read_bytes};
+
+    #[test]
+    fn test_load_content()
+    {
+        let mut content = Content::new("tests/pages/a.html", "tests/pages/a.html", 3600);
+
+        assert_eq!(content.get_uri(), "tests/pages/a.html".to_string());
+        assert!(content.utf8_body().is_ok_and(|b| b == "".to_string()));
+
+        assert!(content.load_from_file().is_ok());
+        assert!(content.utf8_body().is_ok_and(|b| b == "this is /a".to_string()));
+
+        let file = "test_load_content";
+        let path = Path::new("file");
+        if path.exists()
+        {
+            let _ = remove_file(file);
+        }
+        let mut content_missing = Content::new(file, file, 3600);
+        assert!(content_missing.load_from_file().is_err());
+    }
+
+    #[test]
+    fn test_observed_content()
+    {
+        let path = "test_observed_content";
+        let test_content = "this is some test content";
+        let test_content_hash = "2d5bb7c3afbe68c05bcd109d890dca28ceb0105bf529ea1111f9ef8b44b217b9".to_string();
+        let modified_test_content = "this is some modified content";
+        let modified_test_content_hash = "c4ea4898725c3390549d40a19a26a57730730b42050def80f1d157581e33b2db".to_string();
+
+        write_file_bytes(path, test_content.as_bytes());
+
+        let mut content = Content::new(path, path, 3600);
+
+        assert!(content.load_from_file().is_ok());
+        assert!(!content.is_stale());
+        assert_eq!(file_hash(path), read_bytes(test_content_hash));
+        assert!(content.utf8_body().is_ok_and(|b| b == test_content.to_string()));
+        write_file_bytes(path, modified_test_content.as_bytes());
+
+        assert!(content.is_stale());
+        assert_eq!(file_hash(path), read_bytes(modified_test_content_hash));
+        content.refresh();
+        assert!(content.utf8_body().is_ok_and(|b| b == modified_test_content.to_string()));
+
+        let _ = remove_file(path);
+    }
+
+}
+

tests/test_filesystem.rs

@@ -4,9 +4,9 @@ mod common;
 mod filesystem
 {
 
-    use std::fs::remove_file;
+    use std::{fs::remove_file, path::Path};
 
-    use busser::filesystem::{file::{read_file_bytes, read_file_utf8, write_file_bytes, FileNotReadError}, folder::list_dir_by};
+    use busser::filesystem::{file::{read_file_bytes, read_file_utf8, write_file_bytes}, folder::list_dir_by};
     use regex::Regex;
 
 
@@ -15,15 +15,29 @@ mod filesystem
     {
         let expected = "this is /a".as_bytes();
         let actual = read_file_bytes("tests/pages/a.html").unwrap();
-        assert_eq!(actual, expected)
+        assert_eq!(actual, expected);
+
+        let path = Path::new("test_file_error");
+        if path.exists()
+        {
+            let _ = remove_file(path);
+        }
+        assert!(read_file_bytes(path.to_str().unwrap()).is_none());
     }
 
     #[test]
     fn test_read_utf8()
     {
         let expected = "this is /a";
         let actual = read_file_utf8("tests/pages/a.html").unwrap();
-        assert_eq!(actual, expected)
+        assert_eq!(actual, expected);
+
+        let path = Path::new("test_file_error");
+        if path.exists()
+        {
+            let _ = remove_file(path);
+        }
+        assert!(read_file_utf8(path.to_str().unwrap()).is_none());
     }
 
     #[test]
@@ -36,7 +50,7 @@ mod filesystem
         let actual = read_file_utf8("test_write_bytes").unwrap();
         assert_eq!(actual, expected);
 
-        remove_file("test_write_bytes");
+        let _ = remove_file("test_write_bytes");
     }
 
     #[test]
@@ -48,6 +62,5 @@ mod filesystem
         assert!(actual.contains(&"tests/pages/data/jpg.jpg".to_string()));
         assert!(actual.contains(&"tests/pages/data/png.jpg".to_string()));
         assert_eq!(actual.len(), 2);
-
     }
 }

tests/test_page_load.rs

@@ -13,7 +13,7 @@ mod test_page_load
         let pages = get_pages(Some("tests/pages"), None);
 
         assert_eq!(pages.len(), 3);
-        
+
         let paths = HashMap::from(
             [
                 ("tests/pages/a.html", "this is /a"),
@@ -31,7 +31,6 @@ mod test_page_load
             assert_eq!(actual_body, expected_body)
         }
 
-
     }
 
 }