script/dom/html/document_metadata/
processingoptions.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5use std::str::FromStr;
6use std::sync::Arc;
7
8use bytes::{Bytes, BytesMut};
9use cssparser::match_ignore_ascii_case;
10use http::header::HeaderMap;
11use hyper_serde::Serde;
12use mime::Mime;
13use net_traits::fetch::headers::get_decode_and_split_header_name;
14use net_traits::mime_classifier::{MediaType, MimeClassifier};
15use net_traits::policy_container::PolicyContainer;
16use net_traits::request::{
17    CorsSettings, Destination, Initiator, PreloadId, PreloadKey, Referrer, RequestBuilder,
18    RequestClient, RequestId,
19};
20use net_traits::{FetchMetadata, NetworkError, ReferrerPolicy, ResourceFetchTiming};
21pub use nom_rfc8288::complete::LinkDataOwned as LinkHeader;
22use nom_rfc8288::complete::link_lenient as parse_link_header;
23use servo_base::id::WebViewId;
24use servo_url::{ImmutableOrigin, ServoUrl};
25use strum::IntoStaticStr;
26
27use crate::dom::bindings::refcounted::Trusted;
28use crate::dom::bindings::reflector::DomGlobal;
29use crate::dom::bindings::root::DomRoot;
30use crate::dom::csp::{GlobalCspReporting, Violation};
31use crate::dom::document::Document;
32use crate::dom::globalscope::GlobalScope;
33use crate::dom::medialist::MediaList;
34use crate::dom::node::NodeTraits;
35use crate::dom::performance::performanceresourcetiming::InitiatorType;
36use crate::dom::srcset::SourceSet;
37use crate::dom::types::HTMLLinkElement;
38use crate::fetch::fetch::create_a_potential_cors_request;
39use crate::fetch::network_listener::{
40    FetchResponseListener, ResourceTimingListener, submit_timing,
41};
42
43trait ValueForKeyInLinkHeader {
44    fn has_key_in_link_header(&self, key: &str) -> bool;
45    fn value_for_key_in_link_header(&self, key: &str) -> Option<&str>;
46}
47
48impl ValueForKeyInLinkHeader for LinkHeader {
49    fn has_key_in_link_header(&self, key: &str) -> bool {
50        self.params.iter().any(|p| p.key == key)
51    }
52    fn value_for_key_in_link_header(&self, key: &str) -> Option<&str> {
53        let param = self.params.iter().find(|p| p.key == key)?;
54        param.val.as_deref()
55    }
56}
57
58#[derive(PartialEq)]
59pub(crate) enum LinkProcessingPhase {
60    Media,
61    PreMedia,
62}
63
64/// <https://html.spec.whatwg.org/multipage/#link-processing-options>
65#[derive(Debug)]
66pub(crate) struct LinkProcessingOptions {
67    /// <https://html.spec.whatwg.org/multipage/#link-options-href>
68    pub(crate) href: String,
69    /// <https://html.spec.whatwg.org/multipage/#link-options-destination>
70    pub(crate) destination: Destination,
71    /// <https://html.spec.whatwg.org/multipage/#link-options-integrity>
72    pub(crate) integrity: String,
73    /// <https://html.spec.whatwg.org/multipage/#link-options-type>
74    pub(crate) link_type: String,
75    /// <https://html.spec.whatwg.org/multipage/#link-options-nonce>
76    pub(crate) cryptographic_nonce_metadata: String,
77    /// <https://html.spec.whatwg.org/multipage/#link-options-crossorigin>
78    pub(crate) cross_origin: Option<CorsSettings>,
79    /// <https://html.spec.whatwg.org/multipage/#link-options-referrer-policy>
80    pub(crate) referrer_policy: ReferrerPolicy,
81    /// <https://html.spec.whatwg.org/multipage/#link-options-policy-container>
82    pub(crate) policy_container: Arc<PolicyContainer>,
83    /// <https://html.spec.whatwg.org/multipage/#link-options-source-set>
84    pub(crate) source_set: Option<SourceSet>,
85    /// <https://html.spec.whatwg.org/multipage/#link-options-base-url>
86    pub(crate) base_url: ServoUrl,
87    /// <https://html.spec.whatwg.org/multipage/#link-options-origin>
88    pub(crate) origin: ImmutableOrigin,
89    pub(crate) referrer: Referrer,
90    // https://html.spec.whatwg.org/multipage/#link-options-environment
91    pub(crate) request_client: RequestClient,
92    // https://html.spec.whatwg.org/multipage/#link-options-document
93    // TODO
94    // https://html.spec.whatwg.org/multipage/#link-options-on-document-ready
95    // TODO
96    // https://html.spec.whatwg.org/multipage/#link-options-fetch-priority
97    // TODO
98}
99
100impl LinkProcessingOptions {
101    /// <https://html.spec.whatwg.org/multipage/#apply-link-options-from-parsed-header-attributes>
102    fn apply_link_options_from_parsed_header(
103        &mut self,
104        link_object: &LinkHeader,
105        rel: &str,
106    ) -> bool {
107        // Step 1. If rel is "preload":
108        if rel == "preload" {
109            // Step 1.1. If attribs["as"] does not exist, then return false.
110            let Some(as_) = link_object.value_for_key_in_link_header("as") else {
111                return false;
112            };
113            // Step 1.2. Let destination be the result of translating attribs["as"].
114            let Some(destination) = Self::translate_a_preload_destination(as_) else {
115                // Step 1.3. If destination is null, then return false.
116                return false;
117            };
118            // Step 1.4. Set options's destination to destination.
119            self.destination = destination;
120        }
121        // Step 2. If attribs["crossorigin"] exists and is an ASCII case-insensitive match for one of the
122        // CORS settings attribute keywords, then set options's crossorigin to the CORS settings attribute
123        // state corresponding to that keyword.
124        if let Some(cross_origin) = link_object.value_for_key_in_link_header("crossorigin") {
125            self.cross_origin = determine_cors_settings_for_token(cross_origin);
126        }
127        // Step 3. If attribs["integrity"] exists, then set options's integrity to attribs["integrity"].
128        if let Some(integrity) = link_object.value_for_key_in_link_header("integrity") {
129            self.integrity = integrity.to_owned();
130        }
131        // Step 4. If attribs["referrerpolicy"] exists and is an ASCII case-insensitive match for
132        // some referrer policy, then set options's referrer policy to that referrer policy.
133        if let Some(referrer_policy) = link_object.value_for_key_in_link_header("referrerpolicy") {
134            self.referrer_policy = ReferrerPolicy::from(referrer_policy);
135        }
136        // Step 5. If attribs["nonce"] exists, then set options's nonce to attribs["nonce"].
137        if let Some(nonce) = link_object.value_for_key_in_link_header("nonce") {
138            self.cryptographic_nonce_metadata = nonce.to_owned();
139        }
140        // Step 6. If attribs["type"] exists, then set options's type to attribs["type"].
141        if let Some(link_type) = link_object.value_for_key_in_link_header("type") {
142            self.link_type = link_type.to_owned();
143        }
144        // Step 7. If attribs["fetchpriority"] exists and is an ASCII case-insensitive match
145        // for a fetch priority attribute keyword, then set options's fetch priority to that
146        // fetch priority attribute keyword.
147        // TODO
148        // Step 8. Return true.
149        true
150    }
151
152    /// <https://html.spec.whatwg.org/multipage/#process-a-link-header>
153    fn process_link_header(self, rel: &str, document: &Document) {
154        if rel == "preload" {
155            // https://html.spec.whatwg.org/multipage/#link-type-preload:process-a-link-header
156            // The process a link header step for this type of link given a link processing options options
157            // is to preload options.
158            if !self.type_matches_destination() {
159                return;
160            }
161            self.preload(document.window().webview_id(), None, document);
162        }
163    }
164
165    /// <https://html.spec.whatwg.org/multipage/#translate-a-preload-destination>
166    pub(crate) fn translate_a_preload_destination(
167        potential_destination: &str,
168    ) -> Option<Destination> {
169        // Step 2. Return the result of translating destination.
170        Some(match potential_destination {
171            "fetch" => Destination::None,
172            "font" => Destination::Font,
173            "image" => Destination::Image,
174            "script" => Destination::Script,
175            "style" => Destination::Style,
176            "track" => Destination::Track,
177            // Step 1. If destination is not "fetch", "font", "image",
178            // "script", "style", or "track", then return null.
179            _ => return None,
180        })
181    }
182
183    /// <https://html.spec.whatwg.org/multipage/#create-a-link-request>
184    pub(crate) fn create_link_request(self, webview_id: WebViewId) -> Option<RequestBuilder> {
185        // Step 1. Assert: options's href is not the empty string.
186        assert!(!self.href.is_empty());
187
188        // Step 3. Let url be the result of encoding-parsing a URL given options's href, relative to options's base URL.
189        let Ok(url) = ServoUrl::parse_with_base(Some(&self.base_url), &self.href) else {
190            // Step 4. If url is failure, then return null.
191            return None;
192        };
193
194        // Step 5. Let request be the result of creating a potential-CORS request given
195        //         url, options's destination, and options's crossorigin.
196        // Step 6. Set request's policy container to options's policy container.
197        // Step 7. Set request's integrity metadata to options's integrity.
198        // Step 8. Set request's cryptographic nonce metadata to options's cryptographic nonce metadata.
199        // Step 9. Set request's referrer policy to options's referrer policy.
200        // Step 10. Set request's client to options's environment.
201        // FIXME: Step 11. Set request's priority to options's fetch priority.
202        let builder = create_a_potential_cors_request(
203            Some(webview_id),
204            url,
205            self.destination,
206            self.cross_origin,
207            None,
208            self.referrer,
209        )
210        .policy_container(self.policy_container)
211        .client(self.request_client)
212        .initiator(Initiator::Link)
213        .origin(self.origin)
214        .integrity_metadata(self.integrity)
215        .cryptographic_nonce_metadata(self.cryptographic_nonce_metadata)
216        .referrer_policy(self.referrer_policy);
217
218        // Step 12. Return request.
219        Some(builder)
220    }
221
222    /// <https://html.spec.whatwg.org/multipage/#match-preload-type>
223    pub(crate) fn type_matches_destination(&self) -> bool {
224        // Step 1. If type is an empty string, then return true.
225        if self.link_type.is_empty() {
226            return true;
227        }
228        // Step 2. If destination is "fetch", then return true.
229        //
230        // Fetch is handled as an empty string destination in the spec:
231        // https://fetch.spec.whatwg.org/#concept-potential-destination-translate
232        let destination = self.destination;
233        if destination == Destination::None {
234            return true;
235        }
236        // Step 3. Let mimeTypeRecord be the result of parsing type.
237        let Ok(mime_type_record) = Mime::from_str(&self.link_type) else {
238            // Step 4. If mimeTypeRecord is failure, then return false.
239            return false;
240        };
241        // Step 5. If mimeTypeRecord is not supported by the user agent, then return false.
242        //
243        // We currently don't check if we actually support the mime type. Only if we can classify
244        // it according to the spec.
245        let Some(mime_type) = MimeClassifier::get_media_type(&mime_type_record) else {
246            return false;
247        };
248        // Step 6. If any of the following are true:
249        if
250        // destination is "audio" or "video", and mimeTypeRecord is an audio or video MIME type;
251        ((destination == Destination::Audio || destination == Destination::Video) &&
252            mime_type == MediaType::AudioVideo)
253            // destination is a script-like destination and mimeTypeRecord is a JavaScript MIME type;
254            || (destination.is_script_like() && mime_type == MediaType::JavaScript)
255            // destination is "image" and mimeTypeRecord is an image MIME type;
256            || (destination == Destination::Image && mime_type == MediaType::Image)
257            // destination is "font" and mimeTypeRecord is a font MIME type;
258            || (destination == Destination::Font && mime_type == MediaType::Font)
259            // destination is "json" and mimeTypeRecord is a JSON MIME type;
260            || (destination == Destination::Json && mime_type == MediaType::Json)
261            // destination is "style" and mimeTypeRecord's essence is text/css; or
262            || (destination == Destination::Style && mime_type_record == mime::TEXT_CSS)
263            // destination is "track" and mimeTypeRecord's essence is text/vtt,
264            || (destination == Destination::Track && mime_type_record.essence_str() == "text/vtt")
265        {
266            // then return true.
267            return true;
268        }
269        // Step 7. Return false.
270        false
271    }
272
273    /// <https://html.spec.whatwg.org/multipage/#preload>
274    pub(crate) fn preload(
275        mut self,
276        webview_id: WebViewId,
277        link: Option<Trusted<HTMLLinkElement>>,
278        document: &Document,
279    ) {
280        // Step 1. If options's type doesn't match options's destination, then return.
281        //
282        // Handled by callers, since we need to check the previous destination type
283        assert!(self.type_matches_destination());
284        // Step 2. If options's destination is "image" and options's source set is not null,
285        // then set options's href to the result of selecting an image source from options's source set.
286        if self.destination == Destination::Image &&
287            let Some(srcset) = &mut self.source_set
288        {
289            self.href = String::from(
290                srcset
291                    .select_image_source_from_source_set(document)
292                    .unwrap_or_default()
293                    .0,
294            );
295        }
296        // Step 3. Let request be the result of creating a link request given options.
297        let Some(request) = self.create_link_request(webview_id) else {
298            // Step 4. If request is null, then return.
299            return;
300        };
301        let preload_id = PreloadId::default();
302        let request = request.preload_id(preload_id.clone());
303        // Step 5. Let unsafeEndTime be 0.
304        // TODO
305        // Step 6. Let entry be a new preload entry whose integrity metadata is options's integrity.
306        //
307        // This is performed in `CoreResourceManager::fetch`
308        // Step 7. Let key be the result of creating a preload key given request.
309        let key = PreloadKey::new(&request);
310        // Step 8. If options's document is "pending", then set request's initiator type to "early hint".
311        // TODO
312        // Step 9. Let controller be null.
313        // Step 10. Let reportTiming given a Document document be to report timing for controller
314        // given document's relevant global object.
315        let url = request.url.url();
316        let fetch_context = LinkFetchContext {
317            url,
318            link,
319            global: Trusted::new(&document.global()),
320            type_: LinkFetchContextType::Preload,
321            response_body: BytesMut::new(),
322        };
323        document.insert_preloaded_resource(key, preload_id);
324        // Step 11. Set controller to the result of fetching request, with processResponseConsumeBody
325        // set to the following steps given a response response and null, failure, or a byte sequence bodyBytes:
326        document.fetch_background(request, fetch_context);
327    }
328}
329
330pub(crate) fn determine_cors_settings_for_token(token: &str) -> Option<CorsSettings> {
331    match_ignore_ascii_case! { token,
332        "anonymous" => Some(CorsSettings::Anonymous),
333        "use-credentials" => Some(CorsSettings::UseCredentials),
334        _ => None,
335    }
336}
337
338/// <https://html.spec.whatwg.org/multipage/#extract-links-from-headers>
339pub(crate) fn extract_links_from_headers(headers: &Option<Serde<HeaderMap>>) -> Vec<LinkHeader> {
340    // Step 1. Let links be a new list.
341    let mut links = Vec::new();
342    let Some(headers) = headers else {
343        return links;
344    };
345    // Step 2. Let rawLinkHeaders be the result of getting, decoding, and splitting `Link` from headers.
346    let Some(raw_link_headers) = get_decode_and_split_header_name("Link", headers) else {
347        return links;
348    };
349    // Step 3. For each linkHeader of rawLinkHeaders:
350    for link_header in raw_link_headers {
351        // Step 3.1. Let linkObject be the result of parsing linkHeader. [WEBLINK]
352        let Ok(parsed_link_header) = parse_link_header(&link_header) else {
353            continue;
354        };
355        for link_object in parsed_link_header {
356            let Some(link_object) = link_object else {
357                // Step 3.2. If linkObject["target_uri"] does not exist, then continue.
358                continue;
359            };
360            // Step 3.3. Append linkObject to links.
361            links.push(link_object.to_owned());
362        }
363    }
364    // Step 4. Return links.
365    links
366}
367
368/// <https://html.spec.whatwg.org/multipage/#process-link-headers>
369pub(crate) fn process_link_headers(
370    link_headers: &[LinkHeader],
371    document: &Document,
372    phase: LinkProcessingPhase,
373) {
374    let global = document.owner_global();
375    // Step 1. Let links be the result of extracting links from response's header list.
376    //
377    // Already performed once when parsing headers by caller
378    // Step 2. For each linkObject in links:
379    for link_object in link_headers {
380        // Step 2.1. Let rel be linkObject["relation_type"].
381        let Some(rel) = link_object.value_for_key_in_link_header("rel") else {
382            continue;
383        };
384        // Step 2.2. Let attribs be linkObject["target_attributes"].
385        //
386        // Not applicable, that's in `link_object.params`
387        // Step 2.3. Let expectedPhase be "media" if either "srcset", "imagesrcset",
388        // or "media" exist in attribs; otherwise "pre-media".
389        let expected_phase = if link_object.has_key_in_link_header("srcset") ||
390            link_object.has_key_in_link_header("imagesrcset") ||
391            link_object.has_key_in_link_header("media")
392        {
393            LinkProcessingPhase::Media
394        } else {
395            LinkProcessingPhase::PreMedia
396        };
397        // Step 2.4. If expectedPhase is not phase, then continue.
398        if expected_phase != phase {
399            continue;
400        }
401        // Step 2.5. If attribs["media"] exists and attribs["media"] does not match the environment, then continue.
402        if let Some(media) = link_object.value_for_key_in_link_header("media") &&
403            !MediaList::matches_environment(document, media)
404        {
405            continue;
406        }
407        // Step 2.6. Let options be a new link processing options with
408        let mut options = LinkProcessingOptions {
409            href: link_object.url.clone(),
410            destination: Destination::None,
411            integrity: String::new(),
412            link_type: String::new(),
413            cryptographic_nonce_metadata: String::new(),
414            cross_origin: None,
415            referrer_policy: ReferrerPolicy::EmptyString,
416            policy_container: document.policy_container().clone(),
417            source_set: None,
418            origin: document.origin().immutable().to_owned(),
419            base_url: document.base_url(),
420            request_client: global.request_client(None),
421            referrer: global.get_referrer(),
422        };
423        // Step 2.7. Apply link options from parsed header attributes to options given attribs and rel.
424        // If that returned false, then return.
425        if !options.apply_link_options_from_parsed_header(link_object, rel) {
426            return;
427        }
428        // Step 2.8. If attribs["imagesrcset"] exists and attribs["imagesizes"] exists,
429        // then set options's source set to the result of creating a source set given
430        // linkObject["target_uri"], attribs["imagesrcset"], attribs["imagesizes"], and null.
431        if let Some(imagesrcset) = link_object.value_for_key_in_link_header("imagesrcset") &&
432            let Some(imagesizes) = link_object.value_for_key_in_link_header("imagesizes")
433        {
434            options.source_set = Some(SourceSet::create_source_set(
435                &link_object.url,
436                imagesrcset,
437                imagesizes,
438                document,
439            ))
440        }
441        // Step 2.9. Run the process a link header steps for rel given options.
442        options.process_link_header(rel, document);
443    }
444}
445
446#[derive(Clone, IntoStaticStr)]
447#[strum(serialize_all = "lowercase")]
448pub(crate) enum LinkFetchContextType {
449    Prefetch,
450    Preload,
451}
452
453impl From<LinkFetchContextType> for InitiatorType {
454    fn from(other: LinkFetchContextType) -> Self {
455        let name: &'static str = other.into();
456        InitiatorType::LocalName(name.to_owned())
457    }
458}
459
460pub(crate) struct LinkFetchContext {
461    /// The `<link>` element (if any) that caused this fetch
462    pub(crate) link: Option<Trusted<HTMLLinkElement>>,
463
464    pub(crate) global: Trusted<GlobalScope>,
465
466    /// The url being prefetched
467    pub(crate) url: ServoUrl,
468
469    /// The type of fetching we perform, used when report timings.
470    pub(crate) type_: LinkFetchContextType,
471
472    pub(crate) response_body: BytesMut,
473}
474
475impl FetchResponseListener for LinkFetchContext {
476    fn process_request_body(&mut self, _: RequestId) {}
477
478    fn process_response(
479        &mut self,
480        _: &mut js::context::JSContext,
481        _: RequestId,
482        fetch_metadata: Result<FetchMetadata, NetworkError>,
483    ) {
484        _ = fetch_metadata;
485    }
486
487    fn process_response_chunk(
488        &mut self,
489        _: &mut js::context::JSContext,
490        _: RequestId,
491        chunk: Bytes,
492    ) {
493        if matches!(self.type_, LinkFetchContextType::Preload) {
494            self.response_body.extend_from_slice(&chunk);
495        }
496    }
497
498    /// Step 7 of <https://html.spec.whatwg.org/multipage/#link-type-prefetch:fetch-and-process-the-linked-resource-2>
499    /// and step 3.1 of <https://html.spec.whatwg.org/multipage/#link-type-preload:fetch-and-process-the-linked-resource-2>
500    fn process_response_eof(
501        self,
502        cx: &mut js::context::JSContext,
503        _: RequestId,
504        response_result: Result<(), NetworkError>,
505        timing: ResourceFetchTiming,
506    ) {
507        submit_timing(cx, &self, &response_result, &timing);
508
509        // Step 11.6. If processResponse is given, then call processResponse with response.
510        //
511        // Part of Preload
512        //
513        // Step 6. Let processPrefetchResponse be the following steps given a response response and null, failure, or a byte sequence bytesOrNull:
514        //
515        // Part of Prefetch
516        if let Some(link) = self.link.as_ref() {
517            link.root().fire_event_after_response(cx, response_result);
518        }
519    }
520
521    fn process_csp_violations(
522        &mut self,
523        cx: &mut js::context::JSContext,
524        _request_id: RequestId,
525        violations: Vec<Violation>,
526    ) {
527        let global = &self.resource_timing_global();
528        global.report_csp_violations(cx, violations, None, None);
529    }
530
531    fn process_content_length(&mut self, _request_id: RequestId, size: usize) {
532        self.response_body
533            .reserve(size.saturating_sub(self.response_body.len()));
534    }
535}
536
537impl ResourceTimingListener for LinkFetchContext {
538    fn resource_timing_information(&self) -> (InitiatorType, ServoUrl) {
539        (self.type_.clone().into(), self.url.clone())
540    }
541
542    fn resource_timing_global(&self) -> DomRoot<GlobalScope> {
543        self.global.root()
544    }
545}
script/dom/html/document_metadata/processingoptions.rs

script/dom/html/document_metadata/
processingoptions.rs
