range header support

src/error.rs

@@ -15,6 +15,9 @@ pub(crate) enum UploadError {
     #[error("Error parsing string, {0}")]
     ParseString(#[from] std::string::FromUtf8Error),
 
+    #[error("Error parsing request, {0}")]
+    ParseReq(String),
+
     #[error("Error interacting with filesystem, {0}")]
     Io(#[from] std::io::Error),
 
@@ -112,7 +115,8 @@ impl ResponseError for UploadError {
             UploadError::Gif(_)
             | UploadError::DuplicateAlias
             | UploadError::NoFiles
-            | UploadError::Upload(_) => StatusCode::BAD_REQUEST,
+            | UploadError::Upload(_)
+            | UploadError::ParseReq(_) => StatusCode::BAD_REQUEST,
             UploadError::MissingAlias | UploadError::MissingFilename => StatusCode::NOT_FOUND,
             UploadError::InvalidToken => StatusCode::FORBIDDEN,
             _ => StatusCode::INTERNAL_SERVER_ERROR,

src/main.rs

@@ -1,14 +1,12 @@
 use actix_form_data::{Field, Form, Value};
-use actix_web::{
-    client::Client,
-    guard,
-    http::header::{CacheControl, CacheDirective, LastModified},
-    middleware::{Compress, Logger},
-    web, App, HttpResponse, HttpServer,
-};
-use futures::stream::{Stream, TryStreamExt};
+use actix_fs::file;
+use actix_web::{App, HttpResponse, HttpServer, client::Client, guard, http::header::{ACCEPT_RANGES, CONTENT_LENGTH, CacheControl, CacheDirective, ContentRange, ContentRangeSpec, Header, LastModified}, middleware::{Compress, Logger}, web};
+use bytes::Bytes;
+use futures::{StreamExt, stream::{Stream, TryStreamExt}};
 use once_cell::sync::Lazy;
-use std::{collections::HashSet, path::PathBuf, sync::Once, time::SystemTime};
+use std::{
+    collections::HashSet, convert::TryInto, io, path::PathBuf, sync::Once, time::SystemTime,
+};
 use structopt::StructOpt;
 use tracing::{debug, error, info, instrument, Span};
 use tracing_subscriber::EnvFilter;
@@ -486,6 +484,7 @@ async fn details(
 /// Serve files
 #[instrument(skip(manager))]
 async fn serve(
+    req: web::HttpRequest,
     alias: web::Path<String>,
     manager: web::Data<UploadManager>,
 ) -> Result<HttpResponse, UploadError> {
@@ -505,14 +504,81 @@ async fn serve(
         details
     };
 
-    let stream = actix_fs::read_to_stream(path).await?;
+    match req.headers().get("Range") {
+        //Range header exists - return as ranged
+        Some(range_head) => {
+            let range_hdr = range_head.to_str().map_err(|_| {
+                UploadError::ParseReq("Range header contains non-utf8 characters".to_string())
+            })?;
 
-    Ok(srv_response(
+            let range_dashed = range_hdr
+                .split('=')
+                .skip(1)
+                .next()
+                .ok_or(UploadError::ParseReq("Malformed Range header".to_string()))?;
+
+            let range: Vec<u64> = range_dashed
+                .split('-')
+                .map(|s| s.parse::<u64>())
+                .collect::<Result<Vec<u64>, _>>()
+                .map_err(|_| {
+                    UploadError::ParseReq("Cannot parse byte locations in range header".to_string())
+                })?;
+
+
+            let (out_file, _) = file::seek(
+                file::open(path).await?,
+                io::SeekFrom::Current(range[0].try_into().map_err(|_| {
+                    UploadError::ParseReq("Byte locations too high in range header".to_string())
+                })?),
+            )
+            .await?;
+
+            let (out_file, meta) = file::metadata(out_file)
+                .await
+                .map_err(|_| UploadError::Upload("Error reading metadata".to_string()))?;
+
+
+            let whole_to = ((range[1] - range[0]) as f64 / 65_356.0).floor() as usize;
+            let partial_len = ((range[1] - range[0]) % 65_536) as usize;
+
+
+            let stream = file::read_to_stream(out_file)
+                .await?
+                .take(whole_to + 1)
+                .enumerate()
+                .map(move |bytes_res| {
+                    match bytes_res.1 {
+                        Ok(mut bytes) => {
+                            if bytes_res.0 == whole_to {
+                                return Ok(bytes.split_to(partial_len));
+                            }
+                            return Ok(bytes);
+                        }
+                        Err(e) => Err(e),
+                    }
+                });
+
+            return Ok(srv_ranged_response(
                 stream,
                 details.content_type(),
                 7 * DAYS,
                 details.system_time(),
-    ))
+                Some((range[0], range[1])),
+                Some(meta.len()),
+            ));
+        }
+        //No Range header in the request - return the entire document
+        None => {
+            let stream = actix_fs::read_to_stream(path).await?;
+            return Ok(srv_response(
+                stream,
+                details.content_type(),
+                7 * DAYS,
+                details.system_time(),
+            ));
+        }
+    };
 }
 
 // A helper method to produce responses with proper cache headers
@@ -533,6 +599,36 @@ where
             CacheDirective::MaxAge(expires),
             CacheDirective::Extension("immutable".to_owned(), None),
         ]))
+        .set_header(ACCEPT_RANGES, "bytes")
+        .content_type(ext.to_string())
+        .streaming(stream.err_into())
+}
+
+fn srv_ranged_response<S, E>(
+    stream: S,
+    ext: mime::Mime,
+    expires: u32,
+    modified: SystemTime,
+    range: Option<(u64, u64)>,
+    instance_length: Option<u64>,
+) -> HttpResponse
+where
+    S: Stream<Item = Result<bytes::Bytes, E>> + Unpin + 'static,
+    E: Into<UploadError>,
+{
+    HttpResponse::PartialContent()
+        .set(LastModified(modified.into()))
+        .set(CacheControl(vec![
+            CacheDirective::Public,
+            CacheDirective::MaxAge(expires),
+            CacheDirective::Extension("immutable".to_owned(), None),
+        ]))
+        .set(ContentRange(ContentRangeSpec::Bytes {
+            range,
+            instance_length,
+        }))
+        .set_header(CONTENT_LENGTH, range.unwrap().1 - range.unwrap().0)
+        .set_header(ACCEPT_RANGES, "bytes")
         .content_type(ext.to_string())
         .streaming(stream.err_into())
 }