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feat: add baseTokenURI to ERC721Metadata (#1970)
* feat: add baseTokenURI * fix: tests * chore: dev notation * chore: changelog * chore: typo * Remove extra getters, return empty URI by default * Update docs * Rename baseTokenURI to baseURI * Roll back visibility change of tokenURI * Update changelog entry * Version setBaseURI docs * Improve internal names and comments * Fix compilation errors * Add an external getter for baseURI
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‎CHANGELOG.md

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@@ -4,6 +4,7 @@
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### New features
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* `SafeCast.toUintXX`: new library for integer downcasting, which allows for safe operation on smaller types (e.g. `uint32`) when combined with `SafeMath`. ([#1926](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1926))
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* `ERC721Metadata`: added `baseURI`, which can be used for dramatic gas savings when all token URIs share a prefix (e.g. `http://api.myapp.com/tokens/<id>`). ([#1970](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1970))
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### Improvements
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* `ERC777`: `_burn` is now internal, providing more flexibility and making it easier to create tokens that deflate. ([#1908](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1908))

‎contracts/mocks/ERC721FullMock.sol

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@@ -26,4 +26,8 @@ contract ERC721FullMock is ERC721Full, ERC721Mintable, ERC721MetadataMintable, E
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function setTokenURI(uint256 tokenId, string memory uri) public {
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_setTokenURI(tokenId, uri);
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}
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function setBaseURI(string memory baseURI) public {
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_setBaseURI(baseURI);
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}
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}

‎contracts/token/ERC721/ERC721Metadata.sol

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@@ -12,6 +12,9 @@ contract ERC721Metadata is Context, ERC165, ERC721, IERC721Metadata {
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// Token symbol
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string private _symbol;
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// Base URI
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string private _baseURI;
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// Optional mapping for token URIs
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mapping(uint256 => string) private _tokenURIs;
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@@ -52,24 +55,58 @@ contract ERC721Metadata is Context, ERC165, ERC721, IERC721Metadata {
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}
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/**
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* @dev Returns an URI for a given token ID.
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* Throws if the token ID does not exist. May return an empty string.
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* @param tokenId uint256 ID of the token to query
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* @dev Returns the URI for a given token ID. May return an empty string.
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*
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* If the token's URI is non-empty and a base URI was set (via
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* {_setBaseURI}), it will be added to the token ID's URI as a prefix.
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*
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* Reverts if the token ID does not exist.
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*/
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function tokenURI(uint256 tokenId) external view returns (string memory) {
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require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
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return _tokenURIs[tokenId];
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string memory _tokenURI = _tokenURIs[tokenId];
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// Even if there is a base URI, it is only appended to non-empty token-specific URIs
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if (bytes(_tokenURI).length == 0) {
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return "";
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} else {
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// abi.encodePacked is being used to concatenate strings
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return string(abi.encodePacked(_baseURI, _tokenURI));
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}
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}
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/**
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* @dev Returns the base URI set via {_setBaseURI}. This will be
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* automatically added as a preffix in {tokenURI} to each token's URI, when
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* they are non-empty.
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*/
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function baseURI() external view returns (string memory) {
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return _baseURI;
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}
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/**
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* @dev Internal function to set the token URI for a given token.
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*
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* Reverts if the token ID does not exist.
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* @param tokenId uint256 ID of the token to set its URI
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* @param uri string URI to assign
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*
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* TIP: if all token IDs share a prefix (e.g. if your URIs look like
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* `http://api.myproject.com/token/<id>`), use {_setBaseURI} to store
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* it and save gas.
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*/
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function _setTokenURI(uint256 tokenId, string memory uri) internal {
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function _setTokenURI(uint256 tokenId, string memory _tokenURI) internal {
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require(_exists(tokenId), "ERC721Metadata: URI set of nonexistent token");
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_tokenURIs[tokenId] = uri;
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_tokenURIs[tokenId] = _tokenURI;
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}
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/**
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* @dev Internal function to set the base URI for all token IDs. It is
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* automatically added as a prefix to the value returned in {tokenURI}.
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*
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* _Available since v2.5.0._
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*/
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function _setBaseURI(string memory baseURI) internal {
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_baseURI = baseURI;
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}
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/**

‎test/token/ERC721/ERC721Full.test.js

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@@ -72,8 +72,6 @@ contract('ERC721Full', function ([
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});
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describe('metadata', function () {
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const sampleUri = 'mock://mytoken';
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it('has a name', async function () {
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expect(await this.token.name()).to.be.equal(name);
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});
@@ -82,31 +80,68 @@ contract('ERC721Full', function ([
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expect(await this.token.symbol()).to.be.equal(symbol);
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});
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it('sets and returns metadata for a token id', async function () {
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await this.token.setTokenURI(firstTokenId, sampleUri);
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expect(await this.token.tokenURI(firstTokenId)).to.be.equal(sampleUri);
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});
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describe('token URI', function () {
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const baseURI = 'https://api.com/v1/';
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const sampleUri = 'mock://mytoken';
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it('reverts when setting metadata for non existent token id', async function () {
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await expectRevert(
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this.token.setTokenURI(nonExistentTokenId, sampleUri), 'ERC721Metadata: URI set of nonexistent token'
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);
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});
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it('it is empty by default', async function () {
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expect(await this.token.tokenURI(firstTokenId)).to.be.equal('');
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});
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it('can burn token with metadata', async function () {
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await this.token.setTokenURI(firstTokenId, sampleUri);
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await this.token.burn(firstTokenId, { from: owner });
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expect(await this.token.exists(firstTokenId)).to.equal(false);
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});
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it('reverts when queried for non existent token id', async function () {
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await expectRevert(
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this.token.tokenURI(nonExistentTokenId), 'ERC721Metadata: URI query for nonexistent token'
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);
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});
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it('returns empty metadata for token', async function () {
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expect(await this.token.tokenURI(firstTokenId)).to.be.equal('');
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});
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it('can be set for a token id', async function () {
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await this.token.setTokenURI(firstTokenId, sampleUri);
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expect(await this.token.tokenURI(firstTokenId)).to.be.equal(sampleUri);
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});
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it('reverts when querying metadata for non existent token id', async function () {
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await expectRevert(
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this.token.tokenURI(nonExistentTokenId), 'ERC721Metadata: URI query for nonexistent token'
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);
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it('reverts when setting for non existent token id', async function () {
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await expectRevert(
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this.token.setTokenURI(nonExistentTokenId, sampleUri), 'ERC721Metadata: URI set of nonexistent token'
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);
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});
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it('base URI can be set', async function () {
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await this.token.setBaseURI(baseURI);
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expect(await this.token.baseURI()).to.equal(baseURI);
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});
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it('base URI is added as a prefix to the token URI', async function () {
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await this.token.setBaseURI(baseURI);
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await this.token.setTokenURI(firstTokenId, sampleUri);
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expect(await this.token.tokenURI(firstTokenId)).to.be.equal(baseURI + sampleUri);
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});
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it('token URI can be changed by changing the base URI', async function () {
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await this.token.setBaseURI(baseURI);
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await this.token.setTokenURI(firstTokenId, sampleUri);
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const newBaseURI = 'https://api.com/v2/';
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await this.token.setBaseURI(newBaseURI);
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expect(await this.token.tokenURI(firstTokenId)).to.be.equal(newBaseURI + sampleUri);
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});
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it('token URI is empty for tokens with no URI but with base URI', async function () {
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await this.token.setBaseURI(baseURI);
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expect(await this.token.tokenURI(firstTokenId)).to.be.equal('');
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});
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it('tokens with URI can be burnt ', async function () {
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await this.token.setTokenURI(firstTokenId, sampleUri);
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await this.token.burn(firstTokenId, { from: owner });
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expect(await this.token.exists(firstTokenId)).to.equal(false);
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await expectRevert(
142+
this.token.tokenURI(firstTokenId), 'ERC721Metadata: URI query for nonexistent token'
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);
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});
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});
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});
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