feat: Add support for resources containing N3 rules

This is a hacky way to support N3 rules in the loaded resource by first removing the rules from the resource, then loading in the file and then adding the N3 rules again.
The same process is applied upon editing the resource with a sparql patch request.

Author: smessie

app/controllers/index.js

@@ -155,6 +155,9 @@ export default class IndexController extends Controller {
       return;
     }
 
+    // Remove all N3 rules from the resource.
+    const matches = await this.model.removeN3RulesFromResource();
+
     this.fields.forEach((field, i) => {
       field.order = i;
 
@@ -182,6 +185,9 @@ export default class IndexController extends Controller {
 
     await this.store.persist();
 
+    // Re-add the N3 rules to the resource.
+    await this.model.addN3RulesToResource(matches);
+
     this.success = 'Successfully saved the form definition!';
     event.target.disabled = false;
     event.target.innerText = 'Save';
@@ -453,7 +459,7 @@ export default class IndexController extends Controller {
 
     this.form = this.model.loadedFormUri;
     this.model.configureStorageLocations(this.form);
-    await this.model.fetchGraphs();
+    await this.model.fetchGraphs(true);
 
     this.model.loadForm();
 

app/routes/index.js

@@ -27,7 +27,7 @@ export default class IndexRoute extends Route {
     console.log('editing form', form);
     this.configureStorageLocations(form);
 
-    await this.fetchGraphs();
+    await this.fetchGraphs(form !== null);
 
     if (form) {
       this.loadForm();
@@ -64,7 +64,13 @@ export default class IndexRoute extends Route {
       storageLocation;
   }
 
-  async fetchGraphs() {
+  async fetchGraphs(removeN3Rules = false) {
+    // Remove all N3 rules from the resource.
+    let matches;
+    if (removeN3Rules) {
+      matches = await this.removeN3RulesFromResource();
+    }
+
     await this.store.fetchGraphForType('hydra-class', true);
     await this.store.fetchGraphForType('rdf-form', true);
     await this.store.fetchGraphForType('rdf-form-field', true);
@@ -76,6 +82,11 @@ export default class IndexRoute extends Route {
     await this.store.fetchGraphForType('shacl-form', true);
     await this.store.fetchGraphForType('shacl-form-field', true);
     await this.store.fetchGraphForType('shacl-form-option', true);
+
+    // Add N3 rules back to the resource.
+    if (removeN3Rules) {
+      await this.addN3RulesToResource(matches);
+    }
   }
 
   initiateNewRdfForm() {
@@ -116,4 +127,85 @@ export default class IndexRoute extends Route {
     console.log('loaded form', this.form);
     console.log('loaded supportedClass', this.supportedClass);
   }
+
+  async removeN3RulesFromResource() {
+    const fetch = this.solidAuth.session.fetch;
+
+    const response = await fetch(this.loadedFormUri, {
+      method: 'GET',
+    });
+
+    // Get content-type.
+    const contentType = response.headers.get('content-type');
+
+    // Get content.
+    let text = await response.text();
+    console.log(text);
+
+    // Match prefixes.
+    const prefixRegex = /(@prefix|PREFIX)\s+[^:]*:\s*<[^>]*>\s*\.?\n/g;
+    const prefixes = text.match(prefixRegex);
+
+    // Match N3 rules.
+    const rulesRegex =
+      /\{[^{}]*}\s*(=>|[^\s{}]*implies[^\s{}]*)\s*{[^{}]*}\s*\./g;
+    const rules = text.match(rulesRegex);
+    console.log(rules);
+
+    // Remove N3 rules.
+    rules?.forEach((match) => {
+      text = text.replace(match, '');
+    });
+
+    // Save resource without N3 rules.
+    await fetch(this.loadedFormUri, {
+      method: 'PUT',
+      headers: {
+        'Content-Type': contentType,
+      },
+      body: text,
+    });
+
+    return { rules, prefixes };
+  }
+
+  async addN3RulesToResource(matches) {
+    const { rules, prefixes } = matches;
+    const fetch = this.solidAuth.session.fetch;
+
+    const response = await fetch(this.loadedFormUri, {
+      method: 'GET',
+    });
+
+    // Get content-type.
+    const contentType = response.headers.get('content-type');
+
+    // Get content.
+    let text = await response.text();
+
+    // Match prefixes.
+    const prefixRegex = /(@prefix|PREFIX)\s+[^:]*:\s*<[^>]*>\s*\.?\n/g;
+    const matchedPrefixes = text.match(prefixRegex);
+
+    // Add prefixes in front if not already present.
+    prefixes?.forEach((prefix) => {
+      if (!matchedPrefixes?.includes(prefix)) {
+        text = prefix + text;
+      }
+    });
+
+    // Add N3 rules.
+    rules.forEach((match) => {
+      text += match;
+    });
+
+    // Save resource with N3 rules.
+    await fetch(this.loadedFormUri, {
+      method: 'PUT',
+      headers: {
+        'Content-Type': contentType,
+      },
+      body: text,
+    });
+  }
 }