Fixes #3385

Author: abeisgoat

scripts/storage-emulator-integration/tests.ts

@@ -1019,22 +1019,50 @@ describe("Storage emulator", () => {
         });
       });
 
-      it("#setMetadata()", async () => {
-        const metadata = await page.evaluate((filename) => {
-          return firebase
-            .storage()
-            .ref(filename)
-            .updateMetadata({
+      describe("#setMetadata()", () => {
+        it("should allow for custom metadata to be set", async () => {
+          const metadata = await page.evaluate((filename) => {
+            return firebase
+              .storage()
+              .ref(filename)
+              .updateMetadata({
+                customMetadata: {
+                  is_over: "9000",
+                },
+              })
+              .then(() => {
+                return firebase.storage().ref(filename).getMetadata();
+              });
+          }, filename);
+
+          expect(metadata.customMetadata.is_over).to.equal("9000");
+        });
+
+        it("should allow deletion of custom metadata by setting to null", async () => {
+          const setMetadata = await page.evaluate((filename) => {
+            const storageReference = firebase.storage().ref(filename);
+            return storageReference.updateMetadata({
+              contentType: "text/plain",
               customMetadata: {
-                is_over: "9000",
+                removeMe: "please",
               },
-            })
-            .then(() => {
-              return firebase.storage().ref(filename).getMetadata();
             });
-        }, filename);
+          }, filename);
+
+          expect(setMetadata.customMetadata.removeMe).to.equal("please");
 
-        expect(metadata.customMetadata.is_over).to.equal("9000");
+          const nulledMetadata = await page.evaluate((filename) => {
+            const storageReference = firebase.storage().ref(filename);
+            return storageReference.updateMetadata({
+              contentType: "text/plain",
+              customMetadata: {
+                removeMe: null as any,
+              },
+            });
+          }, filename);
+
+          expect(nulledMetadata.customMetadata.removeMe).to.equal(undefined);
+        });
       });
 
       it("#delete()", async () => {

src/emulator/storage/metadata.ts

@@ -88,7 +88,9 @@ export class StoredFileMetadata {
       this.update(incomingMetadata);
     }
 
-    this.applyDownloadTokensFromMetadata();
+
+    this.deleteFieldsSetAsNull();
+    this.setDownloadTokensFromCustomMetadata();
   }
 
   asRulesResource(proposedChanges?: RulesResourceMetadataOverrides): RulesResourceMetadata {
@@ -130,7 +132,7 @@ export class StoredFileMetadata {
     return rulesResource;
   }
 
-  private applyDownloadTokensFromMetadata() {
+  private setDownloadTokensFromCustomMetadata() {
     if (!this.customMetadata) return;
 
     if (this.customMetadata.firebaseStorageDownloadTokens) {
@@ -139,6 +141,31 @@ export class StoredFileMetadata {
     }
   }
 
+  private deleteFieldsSetAsNull() {
+    const deletableFields: (keyof this)[] = [
+      "contentDisposition",
+      "contentType",
+      "contentLanguage",
+      "contentEncoding",
+      "cacheControl",
+    ];
+
+    deletableFields.map((field: keyof this) => {
+      if (this[field] === null) {
+        delete this[field];
+      }
+    });
+
+    if (this.customMetadata) {
+      Object.keys(this.customMetadata).map((key: string) => {
+        if (!this.customMetadata) return;
+        if (this.customMetadata[key] === null) {
+          delete this.customMetadata[key];
+        }
+      });
+    }
+  }
+
   update(incoming: IncomingMetadata): void {
     if (incoming.contentDisposition) {
       this.contentDisposition = incoming.contentDisposition;
@@ -150,7 +177,6 @@ export class StoredFileMetadata {
 
     if (incoming.metadata) {
       this.customMetadata = incoming.metadata;
-      this.applyDownloadTokensFromMetadata();
     }
 
     if (incoming.contentLanguage) {
@@ -171,6 +197,9 @@ export class StoredFileMetadata {
       this.cacheControl = incoming.cacheControl;
     }
 
+    this.setDownloadTokensFromCustomMetadata();
+    this.deleteFieldsSetAsNull();
+
     this._cloudFunctions.dispatch("metadataUpdate", new CloudStorageObjectMetadata(this));
   }