57 lines
1.9 KiB
JavaScript
57 lines
1.9 KiB
JavaScript
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import RetrieveMetadata from './services/wado/retrieveMetadata.js';
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const module = 'RetrieveStudyMetadata';
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// Cache for promises. Prevents unnecessary subsequent calls to the server
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const StudyMetaDataPromises = new Map();
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/**
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* Retrieves study metadata
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*
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* @param {Object} server
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* @param {string} studyInstanceUid The UID of the Study to be retrieved
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* @returns {Promise} that will be resolved with the metadata or rejected with the error
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*/
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export function retrieveStudyMetadata(server, studyInstanceUid) {
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// @TODO: Whenever a study metadata request has failed, its related promise will be rejected once and for all
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// and further requests for that metadata will always fail. On failure, we probably need to remove the
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// corresponding promise from the "StudyMetaDataPromises" map...
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if (!server) {
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throw new Error(`${module}: Required 'server' parameter not provided.`);
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}
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if (!studyInstanceUid) {
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throw new Error(
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`${module}: Required 'studyInstanceUid' parameter not provided.`
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);
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}
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// Already waiting on result? Return cached promise
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if (StudyMetaDataPromises.has(studyInstanceUid)) {
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return StudyMetaDataPromises.get(studyInstanceUid);
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}
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// Create a promise to handle the data retrieval
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const promise = new Promise((resolve, reject) => {
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RetrieveMetadata(server, studyInstanceUid).then(function(data) {
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resolve(data);
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}, reject);
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});
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// Store the promise in cache
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StudyMetaDataPromises.set(studyInstanceUid, promise);
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return promise;
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}
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/**
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* Delete the cached study metadata retrieval promise to ensure that the browser will
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* re-retrieve the study metadata when it is next requested
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*
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* @param {String} studyInstanceUid The UID of the Study to be removed from cache
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*
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*/
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export function deleteStudyMetadataPromise(studyInstanceUid) {
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if (StudyMetaDataPromises.has(studyInstanceUid)) {
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StudyMetaDataPromises.delete(studyInstanceUid);
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}
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}
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