Add multi tags covering all tags with the fixed prefix

Author: rlidwka

CHANGELOG.md

@@ -34,6 +34,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added `styles: { '!!null': 'empty' }` option for dumper
   (serializes `{ foo: null }` as "`foo: `"), #570.
 - Added `replacer` option (similar to option in JSON.stringify), #339.
+- Custom `Tag` can now handle all tags or multiple tags with the same prefix, #385.
 
 ### Fixed
 - Astral characters are no longer encoded by dump/safeDump, #587.

examples/handle_unknown_types.js

@@ -0,0 +1,42 @@
+'use strict';
+
+/*eslint-disable no-console*/
+
+var fs   = require('fs');
+var path = require('path');
+var util = require('util');
+var yaml = require('../');
+
+
+var tags = [ 'scalar', 'sequence', 'mapping' ].map(function (kind) {
+  // first argument here is a prefix, so this type will handle anything starting with !
+  return new yaml.Type('!', {
+    kind: kind,
+    multi: true,
+    construct: function (data, type) {
+      return { type: type, data: data };
+    }
+  });
+});
+
+var SCHEMA = yaml.DEFAULT_SCHEMA.extend(tags);
+
+// do not execute the following if file is required (http://stackoverflow.com/a/6398335)
+if (require.main === module) {
+
+  // And read a document using that schema.
+  fs.readFile(path.join(__dirname, 'handle_unknown_types.yml'), 'utf8', function (error, data) {
+    var loaded;
+
+    if (!error) {
+      loaded = yaml.load(data, { schema: SCHEMA });
+      console.log(util.inspect(loaded, false, 20, true));
+    } else {
+      console.error(error.stack || error.message || String(error));
+    }
+  });
+}
+
+// There are some exports to play with this example interactively.
+module.exports.tags    = tags;
+module.exports.SCHEMA  = SCHEMA;

examples/handle_unknown_types.yml

@@ -0,0 +1,4 @@
+subject: Handling unknown types in JS-YAML
+scalar: !unknown_scalar_tag 123
+sequence: !unknown_sequence_tag [ 1, 2, 3 ]
+mapping: !unknown_mapping_tag { foo: 1, bar: 2 }

lib/loader.js

@@ -1334,6 +1334,7 @@ function composeNode(state, parentIndent, nodeContext, allowToSeek, allowCompact
       hasContent = false,
       typeIndex,
       typeQuantity,
+      typeList,
       type,
       flowIndent,
       blockIndent;
@@ -1459,23 +1460,38 @@ function composeNode(state, parentIndent, nodeContext, allowToSeek, allowCompact
           break;
         }
       }
-    } else if (_hasOwnProperty.call(state.typeMap[state.kind || 'fallback'], state.tag)) {
-      type = state.typeMap[state.kind || 'fallback'][state.tag];
+    } else {
+      if (_hasOwnProperty.call(state.typeMap[state.kind || 'fallback'], state.tag)) {
+        type = state.typeMap[state.kind || 'fallback'][state.tag];
+      } else {
+        // looking for multi type
+        type = null;
+        typeList = state.typeMap.multi[state.kind || 'fallback'];
+
+        for (typeIndex = 0, typeQuantity = typeList.length; typeIndex < typeQuantity; typeIndex += 1) {
+          if (state.tag.slice(0, typeList[typeIndex].tag.length) === typeList[typeIndex].tag) {
+            type = typeList[typeIndex];
+            break;
+          }
+        }
+      }
+
+      if (!type) {
+        throwError(state, 'unknown tag !<' + state.tag + '>');
+      }
 
       if (state.result !== null && type.kind !== state.kind) {
         throwError(state, 'unacceptable node kind for !<' + state.tag + '> tag; it should be "' + type.kind + '", not "' + state.kind + '"');
       }
 
-      if (!type.resolve(state.result)) { // `state.result` updated in resolver if matched
+      if (!type.resolve(state.result, state.tag)) { // `state.result` updated in resolver if matched
         throwError(state, 'cannot resolve a node with !<' + state.tag + '> explicit tag');
       } else {
-        state.result = type.construct(state.result);
+        state.result = type.construct(state.result, state.tag);
         if (state.anchor !== null) {
           state.anchorMap[state.anchor] = state.result;
         }
       }
-    } else {
-      throwError(state, 'unknown tag !<' + state.tag + '>');
     }
   }
 

lib/schema.js

@@ -11,7 +11,10 @@ function compileList(schema, name, result) {
 
   schema[name].forEach(function (currentType) {
     result.forEach(function (previousType, previousIndex) {
-      if (previousType.tag === currentType.tag && previousType.kind === currentType.kind) {
+      if (previousType.tag === currentType.tag &&
+          previousType.kind === currentType.kind &&
+          previousType.multi === currentType.multi) {
+
         exclude.push(previousIndex);
       }
     });
@@ -30,11 +33,22 @@ function compileMap(/* lists... */) {
         scalar: {},
         sequence: {},
         mapping: {},
-        fallback: {}
+        fallback: {},
+        multi: {
+          scalar: [],
+          sequence: [],
+          mapping: [],
+          fallback: []
+        }
       }, index, length;
 
   function collectType(type) {
-    result[type.kind][type.tag] = result['fallback'][type.tag] = type;
+    if (type.multi) {
+      result.multi[type.kind].push(type);
+      result.multi['fallback'].push(type);
+    } else {
+      result[type.kind][type.tag] = result['fallback'][type.tag] = type;
+    }
   }
 
   for (index = 0, length = arguments.length; index < length; index += 1) {
@@ -79,6 +93,10 @@ Schema.prototype.extend = function extend(definition) {
     if (type.loadKind && type.loadKind !== 'scalar') {
       throw new YAMLException('There is a non-scalar type in the implicit list of a schema. Implicit resolving of such types is not supported.');
     }
+
+    if (type.multi) {
+      throw new YAMLException('There is a multi type in the implicit list of a schema. Multi tags can only be listed as explicit.');
+    }
   });
 
   explicit.forEach(function (type) {

lib/type.js

@@ -4,6 +4,7 @@ var YAMLException = require('./exception');
 
 var TYPE_CONSTRUCTOR_OPTIONS = [
   'kind',
+  'multi',
   'resolve',
   'construct',
   'instanceOf',
@@ -51,6 +52,7 @@ function Type(tag, options) {
   this.predicate    = options['predicate']    || null;
   this.represent    = options['represent']    || null;
   this.defaultStyle = options['defaultStyle'] || null;
+  this.multi        = options['multi']        || false;
   this.styleAliases = compileStyleAliases(options['styleAliases'] || null);
 
   if (YAML_NODE_KINDS.indexOf(this.kind) === -1) {

test/issues/0385.js

@@ -0,0 +1,99 @@
+'use strict';
+
+
+const assert = require('assert');
+const yaml = require('../../');
+
+
+describe('Multi tag', function () {
+  it('should process multi tags', function () {
+    let tags = [ 'scalar', 'mapping', 'sequence' ].map(kind =>
+      new yaml.Type('!', {
+        kind,
+        multi: true,
+        resolve: function () {
+          return true;
+        },
+        construct: function (value, tag) {
+          return { kind, tag, value };
+        }
+      })
+    );
+
+    let schema = yaml.DEFAULT_SCHEMA.extend(tags);
+
+    let expected = [
+      {
+        kind: 'scalar',
+        tag: '!t1',
+        value: '123'
+      },
+      {
+        kind: 'sequence',
+        tag: '!t2',
+        value: [ 1, 2, 3 ]
+      },
+      {
+        kind: 'mapping',
+        tag: '!t3',
+        value: { a: 1, b: 2 }
+      }
+    ];
+
+    assert.deepStrictEqual(yaml.load(`
+- !t1 123
+- !t2 [ 1, 2, 3 ]
+- !t3 { a: 1, b: 2 }
+`, {
+      schema: schema
+    }), expected);
+  });
+
+
+  it('should process tags depending on prefix', function () {
+    let tags = [ '!foo', '!bar', '!' ].map(prefix =>
+      new yaml.Type(prefix, {
+        kind: 'scalar',
+        multi: true,
+        resolve: function () {
+          return true;
+        },
+        construct: function (value, tag) {
+          return { prefix, tag, value };
+        }
+      })
+    );
+
+    tags.push(
+      new yaml.Type('!bar', {
+        kind: 'scalar',
+        resolve: function () {
+          return true;
+        },
+        construct: function (value) {
+          return { single: true, value };
+        }
+      })
+    );
+
+    let schema = yaml.DEFAULT_SCHEMA.extend(tags);
+
+    let expected = [
+      { prefix: '!foo', tag: '!foo', value: '1' },
+      { prefix: '!foo', tag: '!foo2', value: '2' },
+      { single: true, value: '3' },
+      { prefix: '!bar', tag: '!bar2', value: '4' },
+      { prefix: '!', tag: '!baz', value: '5' }
+    ];
+
+    assert.deepStrictEqual(yaml.load(`
+- !foo 1
+- !foo2 2
+- !bar 3
+- !bar2 4
+- !baz 5
+`, {
+      schema: schema
+    }), expected);
+  });
+});