Added ENS avatar support to provider (#2185).

packages/providers/src.ts/base-provider.ts

@@ -14,7 +14,7 @@ import { Deferrable, defineReadOnly, getStatic, resolveProperties } from "@ether
 import { Transaction } from "@ethersproject/transactions";
 import { sha256 } from "@ethersproject/sha2";
 import { toUtf8Bytes, toUtf8String } from "@ethersproject/strings";
-import { poll } from "@ethersproject/web";
+import { fetchJson, poll } from "@ethersproject/web";
 
 import bech32 from "bech32";
 
@@ -237,32 +237,59 @@ function base58Encode(data: Uint8Array): string {
     return Base58.encode(concat([ data, hexDataSlice(sha256(sha256(data)), 0, 4) ]));
 }
 
+export interface Avatar {
+    url: string;
+    linkage: Array<{ type: string, content: string }>;
+}
+
+const matchers = [
+    new RegExp("^(https):/\/(.*)$", "i"),
+    new RegExp("^(data):(.*)$", "i"),
+    new RegExp("^(ipfs):/\/(.*)$", "i"),
+    new RegExp("^eip155:[0-9]+/(erc[0-9]+):(.*)$", "i"),
+];
+
+function _parseString(result: string): null | string {
+    try {
+        return toUtf8String(_parseBytes(result));
+    } catch(error) { }
+    return null;
+}
+
+function _parseBytes(result: string): null | string {
+    if (result === "0x") { return null; }
+
+    const offset = BigNumber.from(hexDataSlice(result, 0, 32)).toNumber();
+    const length = BigNumber.from(hexDataSlice(result, offset, offset + 32)).toNumber();
+    return hexDataSlice(result, offset + 32, offset + 32 + length);
+}
+
+
 export class Resolver implements EnsResolver {
     readonly provider: BaseProvider;
 
     readonly name: string;
     readonly address: string;
 
-    constructor(provider: BaseProvider, address: string, name: string) {
+    readonly _resolvedAddress: null | string;
+
+    // The resolvedAddress is only for creating a ReverseLookup resolver
+    constructor(provider: BaseProvider, address: string, name: string, resolvedAddress?: string) {
         defineReadOnly(this, "provider", provider);
         defineReadOnly(this, "name", name);
         defineReadOnly(this, "address", provider.formatter.address(address));
+        defineReadOnly(this, "_resolvedAddress", resolvedAddress);
     }
 
-    async _fetchBytes(selector: string, parameters?: string): Promise<string> {
-        // keccak256("addr(bytes32,uint256)")
-        const transaction = {
+    async _fetchBytes(selector: string, parameters?: string): Promise<null | string> {
+        // e.g. keccak256("addr(bytes32,uint256)")
+        const tx = {
             to: this.address,
             data: hexConcat([ selector, namehash(this.name), (parameters || "0x") ])
         };
 
         try {
-            const result = await this.provider.call(transaction);
-            if (result === "0x") { return null; }
-
-            const offset = BigNumber.from(hexDataSlice(result, 0, 32)).toNumber();
-            const length = BigNumber.from(hexDataSlice(result, offset, offset + 32)).toNumber();
-            return hexDataSlice(result, offset + 32, offset + 32 + length);
+            return _parseBytes(await this.provider.call(tx));
         } catch (error) {
             if (error.code === Logger.errors.CALL_EXCEPTION) { return null; }
             return null;
@@ -374,6 +401,95 @@ export class Resolver implements EnsResolver {
         return address;
     }
 
+    async getAvatar(): Promise<null | Avatar> {
+        const linkage: Array<{ type: string, content: string }> = [ ];
+        try {
+            const avatar = await this.getText("avatar");
+            if (avatar == null) { return null; }
+
+            for (let i = 0; i < matchers.length; i++) {
+                const match = avatar.match(matchers[i]);
+
+                if (match == null) { continue; }
+                switch (match[1]) {
+                    case "https":
+                        linkage.push({ type: "url", content: avatar });
+                        return { linkage, url: avatar };
+
+                    case "data":
+                        linkage.push({ type: "data", content: avatar });
+                        return { linkage, url: avatar };
+
+                    case "ipfs":
+                        linkage.push({ type: "ipfs", content: avatar });
+                        return { linkage, url: `https:/\/gateway.ipfs.io/ipfs/${ avatar.substring(7) }` }
+
+                    case "erc721":
+                    case "erc1155": {
+                        // Depending on the ERC type, use tokenURI(uint256) or url(uint256)
+                        const selector = (match[1] === "erc721") ? "0xc87b56dd": "0x0e89341c";
+                        linkage.push({ type: match[1], content: avatar });
+
+                        // The owner of this name
+                        const owner = (this._resolvedAddress || await this.getAddress());
+
+                        const comps = (match[2] || "").split("/");
+                        if (comps.length !== 2) { return null; }
+
+                        const addr = await this.provider.formatter.address(comps[0]);
+                        const tokenId = hexZeroPad(BigNumber.from(comps[1]).toHexString(), 32);
+
+                        // Check that this account owns the token
+                        if (match[1] === "erc721") {
+                            // ownerOf(uint256 tokenId)
+                            const tokenOwner = this.provider.formatter.callAddress(await this.provider.call({
+                                to: addr, data: hexConcat([ "0x6352211e", tokenId ])
+                            }));
+                            if (owner !== tokenOwner) { return null; }
+                            linkage.push({ type: "owner", content: tokenOwner });
+
+                        } else if (match[1] === "erc1155") {
+                            // balanceOf(address owner, uint256 tokenId)
+                            const balance = BigNumber.from(await this.provider.call({
+                                to: addr, data: hexConcat([ "0x00fdd58e", hexZeroPad(owner, 32), tokenId ])
+                            }));
+                            if (balance.isZero()) { return null; }
+                            linkage.push({ type: "balance", content: balance.toString() });
+                        }
+
+                        // Call the token contract for the metadata URL
+                        const tx = {
+                            to: this.provider.formatter.address(comps[0]),
+                            data: hexConcat([ selector, tokenId ])
+                        };
+                        let metadataUrl = _parseString(await this.provider.call(tx))
+                        if (metadataUrl == null) { return null; }
+                        linkage.push({ type: "metadata-url", content: metadataUrl });
+
+                        // ERC-1155 allows a generic {id} in the URL
+                        if (match[1] === "erc1155") {
+                            metadataUrl = metadataUrl.replace("{id}", tokenId.substring(2));
+                        }
+
+                        // Get the token metadata
+                        const metadata = await fetchJson(metadataUrl);
+
+                        // Pull the image URL out
+                        if (!metadata || typeof(metadata.image) !== "string" || !metadata.image.match(/^https:\/\//i)) {
+                            return null;
+                        }
+                        linkage.push({ type: "metadata", content: JSON.stringify(metadata) });
+                        linkage.push({ type: "url", content: metadata.image });
+
+                        return { linkage, url: metadata.image };
+                    }
+                }
+            }
+        } catch (error) { }
+
+        return null;
+    }
+
     async getContentHash(): Promise<string> {
 
         // keccak256("contenthash()")
@@ -1615,6 +1731,30 @@ export class BaseProvider extends Provider implements EnsProvider {
         return name;
     }
 
+    async getAvatar(nameOrAddress: string): Promise<null | string> {
+        let resolver: Resolver = null;
+        if (isHexString(nameOrAddress)) {
+            // Address; reverse lookup
+            const address = this.formatter.address(nameOrAddress);
+
+            const reverseName = address.substring(2).toLowerCase() + ".addr.reverse";
+
+            const resolverAddress = await this._getResolver(reverseName);
+            if (!resolverAddress) { return null; }
+
+            resolver = new Resolver(this, resolverAddress, "_", address);
+
+        } else {
+            // ENS name; forward lookup
+            resolver = await this.getResolver(nameOrAddress);
+        }
+
+        const avatar = await resolver.getAvatar();
+        if (avatar == null) { return null; }
+
+        return avatar.url;
+    }
+
     perform(method: string, params: any): Promise<any> {
         return logger.throwError(method + " not implemented", Logger.errors.NOT_IMPLEMENTED, { operation: method });
     }

packages/tests/src.ts/test-providers.ts

@@ -1366,3 +1366,30 @@ describe("Bad ENS resolution", function() {
     });
 
 });
+
+describe("Resolve ENS avatar", function() {
+    [
+        { title: "data", name: "data-avatar.tests.eth", value: "data:image/png;base64,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" },
+        { title: "ipfs", name: "ipfs-avatar.tests.eth", value: "https:/\/gateway.ipfs.io/ipfs/QmQsQgpda6JAYkFoeVcj5iPbwV3xRcvaiXv3bhp1VuYUqw" },
+        { title: "url", name: "url-avatar.tests.eth", value: "https:/\/ethers.org/static/logo.png" },
+    ].forEach((test) => {
+        it(`Resolves avatar for ${ test.title }`, async function() {
+            this.timeout(60000);
+            const provider = ethers.getDefaultProvider("ropsten", getApiKeys("ropsten"));
+            const avatar = await provider.getAvatar(test.name);
+            assert.equal(test.value, avatar, "avatar url");
+        });
+    });
+
+    [
+        { title: "ERC-1155", name: "nick.eth", value: "https:/\/lh3.googleusercontent.com/hKHZTZSTmcznonu8I6xcVZio1IF76fq0XmcxnvUykC-FGuVJ75UPdLDlKJsfgVXH9wOSmkyHw0C39VAYtsGyxT7WNybjQ6s3fM3macE" },
+        { title: "ERC-721", name: "brantly.eth", value: "https:/\/wrappedpunks.com:3000/images/punks/2430.png" },
+    ].forEach((test) => {
+        it(`Resolves avatar for ${ test.title }`, async function() {
+            this.timeout(60000);
+            const provider = ethers.getDefaultProvider("homestead", getApiKeys("homestead"));
+            const avatar = await provider.getAvatar(test.name);
+            assert.equal(test.value, avatar, "avatar url");
+        });
+    });
+});