refactor: reorganize policy parsing and loading logic

casbin · Nov 22, 2024 · b416812 · b416812
1 parent 6e7ae07
commit b416812
Showing 1 changed file with 48 additions and 16 deletions.
diff --git a/src/persist/helper.ts b/src/persist/helper.ts
@@ -1,36 +1,47 @@
 import { Model } from '../model';
 import { parse } from 'csv-parse/sync';
 
-export class Helper {
-  public static loadPolicyLine(line: string, model: Model): void {
+export interface IPolicyParser {
+  parse(line: string): string[][] | null;
+}
+
+export class BasicCsvParser implements IPolicyParser {
+  parse(line: string): string[][] | null {
     if (!line || line.trimStart().charAt(0) === '#') {
-      return;
+      return null;
     }
 
-    const rawTokens = parse(line, {
+    return parse(line, {
       delimiter: ',',
       skip_empty_lines: true,
       trim: true,
       relax_quotes: true,
     });
+  }
+}
 
-    if (!rawTokens || rawTokens.length === 0 || !rawTokens[0]) {
-      return;
-    }
+export class BracketAwareCsvParser implements IPolicyParser {
+  private readonly baseParser: IPolicyParser;
 
-    const tokens: string[] = rawTokens[0];
+  constructor(baseParser: IPolicyParser = new BasicCsvParser()) {
+    this.baseParser = baseParser;
+  }
+
+  parse(line: string): string[][] | null {
+    const rawTokens = this.baseParser.parse(line);
+    if (!rawTokens || !rawTokens[0]) {
+      return null;
+    }
 
+    const tokens = rawTokens[0];
     const processedTokens: string[] = [];
     let currentToken = '';
     let bracketCount = 0;
 
     for (const token of tokens) {
       for (const char of token) {
-        if (char === '(') {
-          bracketCount++;
-        } else if (char === ')') {
-          bracketCount--;
-        }
+        if (char === '(') bracketCount++;
+        else if (char === ')') bracketCount--;
       }
 
       currentToken += (currentToken ? ',' : '') + token;
@@ -45,11 +56,24 @@ export class Helper {
       throw new Error(`Unmatched brackets in policy line: ${line}`);
     }
 
-    if (processedTokens.length === 0) {
+    return processedTokens.length > 0 ? [processedTokens] : null;
+  }
+}
+
+export class PolicyLoader {
+  private readonly parser: IPolicyParser;
+
+  constructor(parser: IPolicyParser = new BracketAwareCsvParser()) {
+    this.parser = parser;
+  }
+
+  loadPolicyLine(line: string, model: Model): void {
+    const tokens = this.parser.parse(line);
+    if (!tokens || !tokens[0]) {
       return;
     }
 
-    let key = processedTokens[0].trim();
+    let key = tokens[0][0].trim();
     if (key.startsWith('"') && key.endsWith('"')) {
       key = key.slice(1, -1);
     }
@@ -65,7 +89,7 @@ export class Helper {
       return;
     }
 
-    const values = processedTokens.slice(1).map((v) => {
+    const values = tokens[0].slice(1).map((v) => {
       if (v.startsWith('"') && v.endsWith('"')) {
         v = v.slice(1, -1);
       }
@@ -75,3 +99,11 @@ export class Helper {
     policy.policy.push(values);
   }
 }
+
+export class Helper {
+  private static readonly policyLoader = new PolicyLoader();
+
+  public static loadPolicyLine(line: string, model: Model): void {
+    Helper.policyLoader.loadPolicyLine(line, model);
+  }
+}