Added load balancer support to PocketProvider (#1052).

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

@@ -1,6 +1,7 @@
 "use strict";
 
-import { Network } from "@ethersproject/networks";
+import { Network, Networkish } from "@ethersproject/networks";
+import { getStatic } from "@ethersproject/properties";
 import { ConnectionInfo } from "@ethersproject/web";
 
 import { Logger } from "@ethersproject/logger";
@@ -9,20 +10,63 @@ const logger = new Logger(version);
 
 import { UrlJsonRpcProvider } from "./url-json-rpc-provider";
 
-const defaultApplicationId = "5f7f8547b90218002e9ce9dd";
+// These are load-balancer-based applicatoin IDs
+const defaultApplicationIds: Record<string, string> = {
+    homestead: "6004bcd10040261633ade990",
+    ropsten: "6004bd4d0040261633ade991",
+    rinkeby: "6004bda20040261633ade994",
+    goerli: "6004bd860040261633ade992",
+};
 
 export class PocketProvider extends UrlJsonRpcProvider {
     readonly applicationId: string;
     readonly applicationSecretKey: string;
+    readonly loadBalancer: boolean;
+
+    constructor(network?: Networkish, apiKey?: any) {
+        // We need a bit of creativity in the constructor because
+        // Pocket uses different default API keys based on the network
+
+        if (apiKey == null) {
+            const n = getStatic<(network: Networkish) => Network>(new.target, "getNetwork")(network);
+            if (n) {
+                const applicationId = defaultApplicationIds[n.name];
+                if (applicationId) {
+                    apiKey = {
+                        applicationId: applicationId,
+                        loadBalancer: true
+                    };
+                }
+            }
+
+            // If there was any issue above, we don't know this network
+            if (apiKey == null) {
+                logger.throwError("unsupported network", Logger.errors.INVALID_ARGUMENT, {
+                    argument: "network",
+                    value: network
+                });
+            }
+
+        }
+
+        super(network, apiKey);
+    }
 
     static getApiKey(apiKey: any): any {
-        const apiKeyObj: { applicationId: string, applicationSecretKey: string } = {
-            applicationId: defaultApplicationId,
+        // Most API Providers allow null to get the default configuration, but
+        // Pocket requires the network to decide the default provider, so we
+        // rely on hijacking the constructor to add a sensible default for us
+
+        if (apiKey == null) {
+            logger.throwArgumentError("PocketProvider.getApiKey does not support null apiKey", "apiKey", apiKey);
+        }
+
+        const apiKeyObj: { applicationId: string, applicationSecretKey: string, loadBalancer: boolean } = {
+            applicationId: null,
+            loadBalancer: false,
             applicationSecretKey: null
         };
 
-        if (apiKey == null) { return apiKeyObj; }
-
         // Parse applicationId and applicationSecretKey
         if (typeof (apiKey) === "string") {
             apiKeyObj.applicationId = apiKey;
@@ -35,9 +79,17 @@ export class PocketProvider extends UrlJsonRpcProvider {
 
             apiKeyObj.applicationId = apiKey.applicationId;
             apiKeyObj.applicationSecretKey = apiKey.applicationSecretKey;
+            apiKeyObj.loadBalancer = !!apiKey.loadBalancer;
 
         } else if (apiKey.applicationId) {
+            logger.assertArgument((typeof (apiKey.applicationId) === "string"),
+                "apiKey.applicationId must be a string", "apiKey.applicationId", apiKey.applicationId);
+
             apiKeyObj.applicationId = apiKey.applicationId;
+            apiKeyObj.loadBalancer = !!apiKey.loadBalancer;
+
+        } else {
+            logger.throwArgumentError("unsupported PocketProvider apiKey", "apiKey", apiKey);
         }
 
         return apiKeyObj;
@@ -49,6 +101,15 @@ export class PocketProvider extends UrlJsonRpcProvider {
             case "homestead":
                 host = "eth-mainnet.gateway.pokt.network";
                 break;
+            case "ropsten":
+                host = "eth-ropsten.gateway.pokt.network";
+                break;
+            case "rinkeby":
+                host = "eth-rinkeby.gateway.pokt.network";
+                break;
+            case "goerli":
+                host = "eth-goerli.gateway.pokt.network";
+                break;
             default:
                 logger.throwError("unsupported network", Logger.errors.INVALID_ARGUMENT, {
                     argument: "network",
@@ -56,9 +117,14 @@ export class PocketProvider extends UrlJsonRpcProvider {
                 });
         }
 
-        const connection: ConnectionInfo = {
-            url: (`https:/\/${ host }/v1/${ apiKey.applicationId }`),
-        };
+        let url = null;
+        if (apiKey.loadBalancer) {
+            url = `https:/\/${ host }/v1/lb/${ apiKey.applicationId }`
+        } else {
+            url = `https:/\/${ host }/v1/${ apiKey.applicationId }`
+        }
+
+        const connection: ConnectionInfo = { url };
 
         // Initialize empty headers
         connection.headers = {}
@@ -73,6 +139,6 @@ export class PocketProvider extends UrlJsonRpcProvider {
     }
 
     isCommunityResource(): boolean {
-        return (this.applicationId === defaultApplicationId);
+        return (this.applicationId === defaultApplicationIds[this.network.name]);
     }
 }