Change character validation in tag key to align with server behavior

ChangeLog.md

@@ -4,6 +4,10 @@
 
 ## Upcoming Release
 
+Blob:
+
+- Changed charaters validation against tag key in filtering blobs with tags to align with service side behavior. (issue #2561)
+
 ## 2025.07 Version 3.35.0
 
 General:

src/blob/persistence/QueryInterpreter/QueryParser.ts

@@ -314,16 +314,23 @@ class QueryParser {
     this.query.throw('expecting tag value');
   }
 
-  private ContainsInvalidTagKeyCharacter(key: string): boolean {
+  private validateTagCharacter(key: string) {
     for (let c of key) {
       if (!(c >= 'a' && c <= 'z' ||
         c >= 'A' && c <= 'Z' ||
         c >= '0' && c <= '9' ||
-        c == '_')) {
-        return true;
+        c == ' ' ||
+        c == '+' ||
+        c == '-' ||
+        c == '.' ||
+        c == '/' ||
+        c == ':' ||
+        c == '=' ||
+        c == '_'
+      )) {
+        this.query.throw(`'${c}' not permitted in tag name or value`);
       }
     }
-    return false;
   }
 
   private validateKey(key: string) {
@@ -342,30 +349,14 @@ class QueryParser {
     if (!this.conditionHeader && ((key.length == 0) || (key.length > 128))) {
       this.query.throw('tag must be between 1 and 128 characters in length');
     }
-    if (this.ContainsInvalidTagKeyCharacter(key)) {
-      this.query.throw(`unexpected '${key}'`);
-    }
+    this.validateTagCharacter(key);
   }
 
   private validateValue(value: string) {
     if (!this.conditionHeader && (value.length > 256)) {
       this.query.throw(`tag value must be between 0 and 256 characters in length`);
     }
-    for (let c of value) {
-      if (!(c >= 'a' && c <= 'z' ||
-        c >= 'A' && c <= 'Z' ||
-        c >= '0' && c <= '9' ||
-        c == ' ' ||
-        c == '+' ||
-        c == '-' ||
-        c == '.' ||
-        c == '/' ||
-        c == ':' ||
-        c == '=' ||
-        c == '_')) {
-        this.query.throw(`'${c}' not permitted in tag name or value`);
-      }
-    }
+    this.validateTagCharacter(value);
   }
 
   /**

tests/blob/apis/blob.test.ts

@@ -2434,6 +2434,19 @@ describe("BlobAPIs", () => {
     assert.deepStrictEqual(outputTags1, tags);
   });
 
+  it("get blob tag with ifTags condition - key with special chars @loki @sql", async () => {
+    let tags: Tags = {
+      " key 1 +-.:=_/": '1a',
+      key2: 'a1'
+    };
+    await blobClient.setTags(tags);
+
+    let queryString = `" key 1 +-.:=_/"='1a'`;
+    let outputTags = (await blobClient.getTags({ conditions: { tagConditions: queryString } })).tags;
+    assert.deepStrictEqual(outputTags, tags);
+  });
+
+
   it("get blob tag with long ifTags condition @loki @sql", async () => {
     const tags = {
       tag1: "val1",