feat: Backlinks (#979)

* feat: backlinks * feat: add backlinkDocumentId to documents.list * chore: refactor fix: create and delete backlink handling * fix: guard against self links * feat: basic frontend fix: race condition * styling * test: fix parse ids * self review * linting * feat: Improved link styling * fix: Increase clickable area at bottom of doc / between references * perf: global styles are SLOW
2019-07-07 19:25:45 -07:00
parent 599e5c8f5d
commit 091e542406
23 changed files with 538 additions and 89 deletions
--- a/server/services/backlinks.js
+++ b/server/services/backlinks.js
@@ -0,0 +1,97 @@
+// @flow
+import { difference } from 'lodash';
+import type { DocumentEvent } from '../events';
+import { Document, Revision, Backlink } from '../models';
+import parseDocumentIds from '../../shared/utils/parseDocumentIds';
+
+export default class Backlinks {
+  async on(event: DocumentEvent) {
+    switch (event.name) {
+      case 'documents.publish': {
+        const document = await Document.findByPk(event.modelId);
+        const linkIds = parseDocumentIds(document.text);
+
+        await Promise.all(
+          linkIds.map(async linkId => {
+            const linkedDocument = await Document.findByPk(linkId);
+            if (linkedDocument.id === event.modelId) return;
+
+            await Backlink.findOrCreate({
+              where: {
+                documentId: linkedDocument.id,
+                reverseDocumentId: event.modelId,
+              },
+              defaults: {
+                userId: document.lastModifiedById,
+              },
+            });
+          })
+        );
+
+        break;
+      }
+      case 'documents.update': {
+        // no-op for now
+        if (event.autosave) return;
+
+        // no-op for drafts
+        const document = await Document.findByPk(event.modelId);
+        if (!document.publishedAt) return;
+
+        const [currentRevision, previsionRevision] = await Revision.findAll({
+          where: { documentId: event.modelId },
+          order: [['createdAt', 'desc']],
+          limit: 2,
+        });
+        const previousLinkIds = parseDocumentIds(previsionRevision.text);
+        const currentLinkIds = parseDocumentIds(currentRevision.text);
+        const addedLinkIds = difference(currentLinkIds, previousLinkIds);
+        const removedLinkIds = difference(previousLinkIds, currentLinkIds);
+
+        await Promise.all(
+          addedLinkIds.map(async linkId => {
+            const linkedDocument = await Document.findByPk(linkId);
+            if (linkedDocument.id === event.modelId) return;
+
+            await Backlink.findOrCreate({
+              where: {
+                documentId: linkedDocument.id,
+                reverseDocumentId: event.modelId,
+              },
+              defaults: {
+                userId: currentRevision.userId,
+              },
+            });
+          })
+        );
+
+        await Promise.all(
+          removedLinkIds.map(async linkId => {
+            const document = await Document.findByPk(linkId);
+            await Backlink.destroy({
+              where: {
+                documentId: document.id,
+                reverseDocumentId: event.modelId,
+              },
+            });
+          })
+        );
+        break;
+      }
+      case 'documents.delete': {
+        await Backlink.destroy({
+          where: {
+            reverseDocumentId: event.modelId,
+          },
+        });
+        await Backlink.destroy({
+          where: {
+            documentId: event.modelId,
+          },
+        });
+        break;
+      }
+      default:
+    }
+  }
+}