ERC721URIStorage: add a getter for the token specific URI suffix. (#6175)

Author: Amxx

.changeset/stale-lizards-cheat.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`ERC721URIStorage`: Add `_suffixURI`, an internal getter for retrieving the custom tokenURI without the base prefix.

contracts/token/ERC721/extensions/ERC721URIStorage.sol

@@ -28,16 +28,16 @@ abstract contract ERC721URIStorage is IERC4906, ERC721 {
     function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
         _requireOwned(tokenId);
 
-        string memory _tokenURI = _tokenURIs[tokenId];
         string memory base = _baseURI();
+        string memory suffix = _suffixURI(tokenId);
 
         // If there is no base URI, return the token URI.
         if (bytes(base).length == 0) {
-            return _tokenURI;
+            return suffix;
         }
         // If both are set, concatenate the baseURI and tokenURI (via string.concat).
-        if (bytes(_tokenURI).length > 0) {
-            return string.concat(base, _tokenURI);
+        if (bytes(suffix).length > 0) {
+            return string.concat(base, suffix);
         }
 
         return super.tokenURI(tokenId);
@@ -52,4 +52,11 @@ abstract contract ERC721URIStorage is IERC4906, ERC721 {
         _tokenURIs[tokenId] = _tokenURI;
         emit MetadataUpdate(tokenId);
     }
+
+    /**
+     * @dev Returns the suffix part of the tokenURI for `tokenId`.
+     */
+    function _suffixURI(uint256 tokenId) internal view virtual returns (string memory) {
+        return _tokenURIs[tokenId];
+    }
 }

test/token/ERC721/extensions/ERC721URIStorage.test.js

@@ -31,18 +31,22 @@ describe('ERC721URIStorage', function () {
     });
 
     it('it is empty by default', async function () {
-      expect(await this.token.tokenURI(tokenId)).to.equal('');
+      await expect(this.token.$_suffixURI(tokenId)).to.eventually.equal('');
+      await expect(this.token.tokenURI(tokenId)).to.eventually.equal('');
     });
 
     it('reverts when queried for non existent token id', async function () {
+      await expect(this.token.$_suffixURI(tokenId)).to.eventually.equal('');
       await expect(this.token.tokenURI(nonExistentTokenId))
         .to.be.revertedWithCustomError(this.token, 'ERC721NonexistentToken')
         .withArgs(nonExistentTokenId);
     });
 
     it('can be set for a token id', async function () {
       await this.token.$_setTokenURI(tokenId, sampleUri);
-      expect(await this.token.tokenURI(tokenId)).to.equal(sampleUri);
+
+      await expect(this.token.$_suffixURI(tokenId)).to.eventually.equal(sampleUri);
+      await expect(this.token.tokenURI(tokenId)).to.eventually.equal(sampleUri);
     });
 
     it('setting the uri emits an event', async function () {
@@ -58,38 +62,43 @@ describe('ERC721URIStorage', function () {
 
       // value will be accessible after mint
       await this.token.$_mint(this.owner, nonExistentTokenId);
-      expect(await this.token.tokenURI(nonExistentTokenId)).to.equal(sampleUri);
+      await expect(this.token.tokenURI(nonExistentTokenId)).to.eventually.equal(sampleUri);
     });
 
     it('base URI can be set', async function () {
       await this.token.setBaseURI(baseURI);
-      expect(await this.token.$_baseURI()).to.equal(baseURI);
+      await expect(this.token.$_baseURI()).to.eventually.equal(baseURI);
     });
 
     it('base URI is added as a prefix to the token URI', async function () {
       await this.token.setBaseURI(baseURI);
       await this.token.$_setTokenURI(tokenId, sampleUri);
 
-      expect(await this.token.tokenURI(tokenId)).to.equal(baseURI + sampleUri);
+      await expect(this.token.$_suffixURI(tokenId)).to.eventually.equal(sampleUri);
+      await expect(this.token.tokenURI(tokenId)).to.eventually.equal(baseURI + sampleUri);
     });
 
     it('token URI can be changed by changing the base URI', async function () {
       await this.token.setBaseURI(baseURI);
       await this.token.$_setTokenURI(tokenId, sampleUri);
 
       await this.token.setBaseURI(otherBaseURI);
-      expect(await this.token.tokenURI(tokenId)).to.equal(otherBaseURI + sampleUri);
+
+      await expect(this.token.$_suffixURI(tokenId)).to.eventually.equal(sampleUri);
+      await expect(this.token.tokenURI(tokenId)).to.eventually.equal(otherBaseURI + sampleUri);
     });
 
     it('tokenId is appended to base URI for tokens with no URI', async function () {
       await this.token.setBaseURI(baseURI);
 
-      expect(await this.token.tokenURI(tokenId)).to.equal(baseURI + tokenId);
+      await expect(this.token.$_suffixURI(tokenId)).to.eventually.equal('');
+      await expect(this.token.tokenURI(tokenId)).to.eventually.equal(baseURI + tokenId);
     });
 
     it('tokens without URI can be burnt ', async function () {
       await this.token.$_burn(tokenId);
 
+      await expect(this.token.$_suffixURI(tokenId)).to.eventually.equal('');
       await expect(this.token.tokenURI(tokenId))
         .to.be.revertedWithCustomError(this.token, 'ERC721NonexistentToken')
         .withArgs(tokenId);
@@ -100,6 +109,7 @@ describe('ERC721URIStorage', function () {
 
       await this.token.$_burn(tokenId);
 
+      await expect(this.token.$_suffixURI(tokenId)).to.eventually.equal(sampleUri);
       await expect(this.token.tokenURI(tokenId))
         .to.be.revertedWithCustomError(this.token, 'ERC721NonexistentToken')
         .withArgs(tokenId);
@@ -110,12 +120,15 @@ describe('ERC721URIStorage', function () {
 
       await this.token.$_burn(tokenId);
 
+      await expect(this.token.$_suffixURI(tokenId)).to.eventually.equal(sampleUri);
       await expect(this.token.tokenURI(tokenId))
         .to.be.revertedWithCustomError(this.token, 'ERC721NonexistentToken')
         .withArgs(tokenId);
 
       await this.token.$_mint(this.owner, tokenId);
-      expect(await this.token.tokenURI(tokenId)).to.equal(sampleUri);
+
+      await expect(this.token.$_suffixURI(tokenId)).to.eventually.equal(sampleUri);
+      await expect(this.token.tokenURI(tokenId)).to.eventually.equal(sampleUri);
     });
   });
 });