Abstracted JSON-RPC parameter generation for others to use.

packages/providers/src.ts/json-rpc-provider.ts

@@ -330,28 +330,76 @@ export class JsonRpcProvider extends BaseProvider {
         });
     }
 
-    perform(method: string, params: any): Promise<any> {
+    prepareRequest(method: string, params: any): [ string, Array<any> ] {
         switch (method) {
             case "getBlockNumber":
-                return this.send("eth_blockNumber", []);
+                return [ "eth_blockNumber", [] ];
 
             case "getGasPrice":
-                return this.send("eth_gasPrice", []);
+                return [ "eth_gasPrice", [] ];
 
             case "getBalance":
-                return this.send("eth_getBalance", [ getLowerCase(params.address), params.blockTag ]);
+                return [ "eth_getBalance", [ getLowerCase(params.address), params.blockTag ] ];
 
             case "getTransactionCount":
-                return this.send("eth_getTransactionCount", [ getLowerCase(params.address), params.blockTag ]);
+                return [ "eth_getTransactionCount", [ getLowerCase(params.address), params.blockTag ] ];
 
             case "getCode":
-                return this.send("eth_getCode", [ getLowerCase(params.address), params.blockTag ]);
+                return [ "eth_getCode", [ getLowerCase(params.address), params.blockTag ] ];
 
             case "getStorageAt":
-                return this.send("eth_getStorageAt", [ getLowerCase(params.address), params.position, params.blockTag ]);
+                return [ "eth_getStorageAt", [ getLowerCase(params.address), params.position, params.blockTag ] ];
 
             case "sendTransaction":
-                return this.send("eth_sendRawTransaction", [ params.signedTransaction ]).catch((error) => {
+                return [ "eth_sendRawTransaction", [ params.signedTransaction ] ]
+
+            case "getBlock":
+                if (params.blockTag) {
+                    return [ "eth_getBlockByNumber", [ params.blockTag, !!params.includeTransactions ] ];
+                } else if (params.blockHash) {
+                    return [ "eth_getBlockByHash", [ params.blockHash, !!params.includeTransactions ] ];
+                }
+                return null;
+
+            case "getTransaction":
+                return [ "eth_getTransactionByHash", [ params.transactionHash ] ];
+
+            case "getTransactionReceipt":
+                return [ "eth_getTransactionReceipt", [ params.transactionHash ] ];
+
+            case "call": {
+                const hexlifyTransaction = getStatic<(t: TransactionRequest, a?: { [key: string]: boolean }) => { [key: string]: string }>(this.constructor, "hexlifyTransaction");
+                return [ "eth_call", [ hexlifyTransaction(params.transaction, { from: true }), params.blockTag ] ];
+            }
+
+            case "estimateGas": {
+                const hexlifyTransaction = getStatic<(t: TransactionRequest, a?: { [key: string]: boolean }) => { [key: string]: string }>(this.constructor, "hexlifyTransaction");
+                return [ "eth_estimateGas", [ hexlifyTransaction(params.transaction, { from: true }) ] ];
+            }
+
+            case "getLogs":
+                if (params.filter && params.filter.address != null) {
+                    params.filter.address = getLowerCase(params.filter.address);
+                }
+                return [ "eth_getLogs", [ params.filter ] ];
+
+            default:
+                break;
+        }
+
+        return null;
+    }
+
+    perform(method: string, params: any): Promise<any> {
+        const args = this.prepareRequest(method,  params);
+
+        if (args == null) {
+            logger.throwError(method + " not implemented", Logger.errors.NOT_IMPLEMENTED, { operation: method });
+        }
+
+        // We need a little extra logic to process errors from sendTransaction
+        if (method === "sendTransaction") {
+            return this.send(args[0], args[1]).catch((error) => {
                 if (error.responseText) {
                     // "insufficient funds for gas * price + value"
                     if (error.responseText.indexOf("insufficient funds") > 0) {
@@ -368,42 +416,9 @@ export class JsonRpcProvider extends BaseProvider {
                 }
                 throw error;
             });
-
-            case "getBlock":
-                if (params.blockTag) {
-                    return this.send("eth_getBlockByNumber", [ params.blockTag, !!params.includeTransactions ]);
-                } else if (params.blockHash) {
-                    return this.send("eth_getBlockByHash", [ params.blockHash, !!params.includeTransactions ]);
-                }
-                return logger.throwArgumentError("invalid block tag or block hash", "params", params);
-
-            case "getTransaction":
-                return this.send("eth_getTransactionByHash", [ params.transactionHash ]);
-
-            case "getTransactionReceipt":
-                return this.send("eth_getTransactionReceipt", [ params.transactionHash ]);
-
-            case "call": {
-                const hexlifyTransaction = getStatic<(t: TransactionRequest, a?: { [key: string]: boolean }) => { [key: string]: string }>(this.constructor, "hexlifyTransaction");
-                return this.send("eth_call", [ hexlifyTransaction(params.transaction, { from: true }), params.blockTag ]);
         }
 
-            case "estimateGas": {
+        return this.send(args[0], args[1])
-                const hexlifyTransaction = getStatic<(t: TransactionRequest, a?: { [key: string]: boolean }) => { [key: string]: string }>(this.constructor, "hexlifyTransaction");
-                return this.send("eth_estimateGas", [ hexlifyTransaction(params.transaction, { from: true }) ]);
-            }
-
-            case "getLogs":
-                if (params.filter && params.filter.address != null) {
-                    params.filter.address = getLowerCase(params.filter.address);
-                }
-                return this.send("eth_getLogs", [ params.filter ]);
-
-            default:
-                break;
-        }
-
-        return logger.throwError(method + " not implemented", Logger.errors.NOT_IMPLEMENTED, { operation: method });
     }
 
     _startEvent(event: Event): void {
@@ -466,8 +481,11 @@ export class JsonRpcProvider extends BaseProvider {
     //  - gasLimit => gas
     //  - All values hexlified
     //  - All numeric values zero-striped
+    //  - All addresses are lowercased
     // NOTE: This allows a TransactionRequest, but all values should be resolved
     //       before this is called
+    // @TODO: This will likely be removed in future versions and prepareRequest
+    //        will be the preferred method for this.
     static hexlifyTransaction(transaction: TransactionRequest, allowExtra?: { [key: string]: boolean }): { [key: string]: string } {
         // Check only allowed properties are given
         const allowed = shallowCopy(allowedTransactionKeys);