From ff2bbf41ca4affe3ea0d57a30e03efa734a8b0ab Mon Sep 17 00:00:00 2001 From: flamingos-cant <45780476+flamingo-cant-draw@users.noreply.github.com> Date: Wed, 4 Dec 2024 13:29:50 +0000 Subject: [PATCH] Use magic number to detemine file type (#5225) * Revert "Guess image mime type from file extension (fixes #5196) (#5212)" This reverts commit 63ea99d38ade254bd428b5d031be0feec123315f. * Use magic numbers to determine file type. * fmt * Don't wrap response in an option * Regen Cargo.lock * Clean-up + guess mime type from extension if server is unresponsive * Move some things about. * Some cleanup. * Removing comment lines. --------- Co-authored-by: Dessalines --- Cargo.lock | 23 +++++++++++- crates/api_common/Cargo.toml | 1 + crates/api_common/src/request.rs | 60 ++++++++++++++++++-------------- 3 files changed, 57 insertions(+), 27 deletions(-) diff --git a/Cargo.lock b/Cargo.lock index b000f9741..bf0dac6e8 100644 --- a/Cargo.lock +++ b/Cargo.lock @@ -779,6 +779,17 @@ dependencies = [ "nom", ] +[[package]] +name = "cfb" +version = "0.7.3" +source = "registry+https://github.com/rust-lang/crates.io-index" +checksum = "d38f2da7a0a2c4ccf0065be06397cc26a81f4e528be095826eee9d4adbb8c60f" +dependencies = [ + "byteorder", + "fnv", + "uuid", +] + [[package]] name = "cfg-if" version = "1.0.0" @@ -2347,6 +2358,15 @@ dependencies = [ "serde", ] +[[package]] +name = "infer" +version = "0.16.0" +source = "registry+https://github.com/rust-lang/crates.io-index" +checksum = "bc150e5ce2330295b8616ce0e3f53250e53af31759a9dbedad1621ba29151847" +dependencies = [ + "cfb", +] + [[package]] name = "inout" version = "0.1.3" @@ -2507,6 +2527,7 @@ dependencies = [ "encoding_rs", "enum-map", "futures", + "infer", "jsonwebtoken", "lemmy_db_schema", "lemmy_db_views", @@ -2878,7 +2899,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index" checksum = "4979f22fdb869068da03c9f7528f8297c6fd2606bc3a4affe42e6a823fdb8da4" dependencies = [ "cfg-if", - "windows-targets 0.48.5", + "windows-targets 0.52.6", ] [[package]] diff --git a/crates/api_common/Cargo.toml b/crates/api_common/Cargo.toml index 3ae14717d..74a0390ca 100644 --- a/crates/api_common/Cargo.toml +++ b/crates/api_common/Cargo.toml @@ -66,6 +66,7 @@ enum-map = { workspace = true } urlencoding = { workspace = true } mime = { version = "0.3.17", optional = true } mime_guess = "2.0.5" +infer = "0.16.0" webpage = { version = "2.0", default-features = false, features = [ "serde", ], optional = true } diff --git a/crates/api_common/src/request.rs b/crates/api_common/src/request.rs index cc506b896..c6f86b806 100644 --- a/crates/api_common/src/request.rs +++ b/crates/api_common/src/request.rs @@ -23,6 +23,7 @@ use lemmy_utils::{ REQWEST_TIMEOUT, VERSION, }; +use mime::{Mime, TEXT_HTML}; use reqwest::{ header::{CONTENT_TYPE, RANGE}, Client, @@ -63,47 +64,54 @@ pub async fn fetch_link_metadata(url: &Url, context: &LemmyContext) -> LemmyResu .await? .error_for_status()?; - // In some cases servers send a wrong mime type for images, which prevents thumbnail - // generation. To avoid this we also try to guess the mime type from file extension. - let content_type = mime_guess::from_path(url.path()) - .first() - // If you can guess that its an image type, then return that first. - .filter(|guess| guess.type_() == mime::IMAGE) - // Otherwise, get the content type from the headers - .or( - response - .headers() - .get(CONTENT_TYPE) - .and_then(|h| h.to_str().ok()) - .and_then(|h| h.parse().ok()), - ); + let mut content_type: Option = response + .headers() + .get(CONTENT_TYPE) + .and_then(|h| h.to_str().ok()) + .and_then(|h| h.parse().ok()) + // If we don't get a content_type from the response (e.g. if the server is down), + // then try to infer the content_type from the file extension. + .or(mime_guess::from_path(url.path()).first()); let opengraph_data = { - // if the content type is not text/html, we don't need to parse it let is_html = content_type .as_ref() .map(|c| { - (c.type_() == mime::TEXT && c.subtype() == mime::HTML) - || - // application/xhtml+xml is a subset of HTML - (c.type_() == mime::APPLICATION && c.subtype() == "xhtml") + // application/xhtml+xml is a subset of HTML + let application_xhtml: Mime = "application/xhtml+xml".parse::().unwrap_or(TEXT_HTML); + let allowed_mime_types = [TEXT_HTML.essence_str(), application_xhtml.essence_str()]; + allowed_mime_types.contains(&c.essence_str()) }) - .unwrap_or(false); - if !is_html { - Default::default() - } else { + .unwrap_or_default(); + + if is_html { // Can't use .text() here, because it only checks the content header, not the actual bytes // https://github.com/LemmyNet/lemmy/issues/1964 - // So we want to do deep inspection of the actually returned bytes but need to be careful not - // spend too much time parsing binary data as HTML - + // So we want to do deep inspection of the actually returned bytes but need to be careful + // not spend too much time parsing binary data as HTML // only take first bytes regardless of how many bytes the server returns let html_bytes = collect_bytes_until_limit(response, bytes_to_fetch).await?; extract_opengraph_data(&html_bytes, url) .map_err(|e| info!("{e}")) .unwrap_or_default() + } else { + let is_octet_type = content_type + .as_ref() + .map(|c| c.subtype() == "octet-stream") + .unwrap_or_default(); + + // Overwrite the content type if its an octet type + if is_octet_type { + // Don't need to fetch as much data for this as we do with opengraph + let octet_bytes = collect_bytes_until_limit(response, 512).await?; + content_type = + infer::get(&octet_bytes).map_or(content_type, |t| t.mime_type().parse().ok()); + } + + Default::default() } }; + Ok(LinkMetadata { opengraph_data, content_type: content_type.map(|c| c.to_string()),