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