wala-rust

meta.rs (6566B)

---

 //! The `meta` module is an optional feature which stores the MIME type value from the
 //! `Content-Type` header of a client `PUT` request.
 //!
 //! The MIME type is stored on the server under the same file identifier as the content but with a
 //! postfix '.meta'.
 //!
 //! A check is performed to validate that the specified value is a valid MIME type string. However,
 //! no further check is performed to attempt to verify whether the declared MIME type correctly
 //! describes the file contents.
 //!
 //! For subsequent `GET` requests for the same content, the stored MIME type will be used as the
 //! `Content-Type` header.
 //! 
 //! If no MIME type was specified for the content, or if the feature is not enabled, the
 //! `Content-Type` header will always be `application/octet-stream`
 //!
 //! Any subsequent `PUT` for the same content specifying a `Content-Type` header will _overwrite_
 //! the previously stored MIME type.
 //!
 //! There is no feature to _delete_ the MIME type association from the server. However, setting the MIME
 //! type explicitly to `application/octet-stream` will achieve the same result as for records that
 //! do not have a MIME type association.
 use std::fs::{
     File,
     read,
 };
 use std::path::{
     Path,
     PathBuf,
 };
 use std::io::Write;
 use std::str::FromStr;
 use mime::Mime;
 use hex;
 
 use log::{debug, error};
 
 
 fn meta_path(path: &Path, digest: &Vec<u8>) -> Result<PathBuf, std::io::Error> {
     let digest_hex = hex::encode(digest);
     let fp = path.join(digest_hex);
 
     let mut path_canon = match fp.canonicalize() {
         Ok(v) => {
             v
         },
         Err(e) => {
             debug!("err {:?} {:?}", e, fp);
             return Err(e);
         }
     };
 
     path_canon.set_extension("meta");
     Ok(path_canon)
 }
 
 fn filename_path(path: &Path, digest: &Vec<u8>) -> Result<PathBuf, std::io::Error> {
     let digest_hex = hex::encode(digest);
     let fp = path.join(digest_hex);
 
     let mut path_canon = match fp.canonicalize() {
         Ok(v) => {
             v
         },
         Err(e) => {
             return Err(e);
         }
     };
 
     path_canon.set_extension("filename");
     Ok(path_canon)
 }
 
 
 /// Set a MIME type for the specified content.
 ///
 /// # Arguments
 ///
 /// * `path` - Absolute path to storage diectory.
 /// * `digest` - Immutable reference to content.
 /// * `typ` - MIME type to store for the content.
 pub fn register_type(path: &Path, digest: &Vec<u8>, typ: Mime) -> Result<(), std::io::Error> {
     match meta_path(path, digest) {
         Ok(v) => {
             match File::create(v) {
                 Ok(mut f) => {
                     f.write(typ.as_ref().as_bytes());
                 }
                 Err(e) => {
                     return Err(e);
                 }
             };
         },
         _ => {},
     };
     Ok(())
 }
 
 
 /// Set a MIME type for the specified content.
 ///
 /// # Arguments
 ///
 /// * `path` - Absolute path to storage diectory.
 /// * `digest` - Immutable reference to content.
 /// * `typ` - MIME type to store for the content.
 pub fn register_filename(path: &Path, digest: &Vec<u8>, name: String) -> Result<(), std::io::Error> {
     match filename_path(path, digest) {
         Ok(v) => {
             match File::create(v) {
                 Ok(mut f) => {
                     f.write(name.as_str().as_bytes());
                     debug!("wrote to {:?}", f);
                 }
                 Err(e) => {
                     return Err(e);
                 }
             };
         },
         _ => {},
     };
     Ok(())
 }
 
 /// Retrieve the MIME type for the specified content.
 ///
 /// # Arguments
 ///
 /// * `path` - Absolute path to storage diectory.
 /// * `digest` - Immutable reference to content.
 pub fn get_type(path: &Path, digest: &Vec<u8>) -> Option<Mime> {
     let digest_hex = hex::encode(digest);
     match meta_path(path, digest) {
         Ok(v) => {
             match read(v) {
                 Ok(r) => {
                     let mime_str = String::from_utf8(r).unwrap();
                     debug!("content type {} retrieved for {}", &mime_str, &digest_hex);
                     let mime = Mime::from_str(mime_str.as_str()).unwrap();
                     return Some(mime);
                 },
                 Err(e) => {
                     debug!("meta type file not found for {}: {}", &digest_hex, e);
                 },
             };
         },
         _ => {},
     };
     None
 }
 
 
 /// Retrieve the alternate filename for the specified content.
 ///
 /// # Arguments
 ///
 /// * `path` - Absolute path to storage diectory.
 /// * `digest` - Immutable reference to content.
 pub fn get_filename(path: &Path, digest: &Vec<u8>) -> Option<String> {
     let digest_hex = hex::encode(digest);
     match filename_path(path, digest) {
         Ok(v) => {
             match read(v) {
                 Ok(r) => {
                     let filename_str = String::from_utf8(r).unwrap();
                     debug!("filename {} retrieved for {}", &filename_str, &digest_hex);
                     return Some(filename_str);
                 },
                 Err(e) => {
                     debug!("filename file not found for {}: {}", &digest_hex, e);
                 },
             };
         },
         _ => {},
     };
     None
 }
 
 #[cfg(test)]
 mod tests {
     use hex;
     use std::str::FromStr;
     use tempfile::tempdir;
     use std::path::Path;
     use std::fs::{
         write,
         File,
     };
 
     use mime::Mime;
 
     use env_logger;
     use log::{debug, info, error};
 
     use super::{
         register_type,
         register_filename,
         get_type,
         get_filename,
     };
 
     #[test]
     fn test_meta_mime() {
         let d = tempdir().unwrap();
         let dp = d.path();
         let url = "deadbeef";
         let digest = hex::decode(&url).unwrap();
         let mime_type = Mime::from_str("application/zip").unwrap();
 
         let fp = dp.join(&url);
         write(&fp, b"foo");
 
         register_type(&dp, &digest, mime_type.clone());
         let mime_type_recovered = get_type(&dp, &digest).unwrap();
         assert_eq!(mime_type_recovered, mime_type);
     }
 
     #[test]
     fn test_meta_filename() {
         let d = tempdir().unwrap();
         let dp = d.path();
         let url = "deadbeef";
         let digest = hex::decode(&url).unwrap();
         let filename = "foo.zip";
 
         let fp = dp.join(&url);
         write(&fp, b"foo");
 
         register_filename(&dp, &digest, String::from(filename));
         let filename_recovered = get_filename(&dp, &digest).unwrap();
         assert_eq!(filename_recovered, filename);
     }
 }