Dynamic neow3j lib version for Java smart contract template. Fixes #48

CHANGELOG.md

@@ -8,6 +8,7 @@ Check [Keep a Changelog](http://keepachangelog.com/) for recommendations on how
 
 ### Changed
 
+- Creating a Java smart contract automatically targets the latest version of neow3j (per Maven Central)
 - Make use of the ms-dotnettools.vscode-dotnet-sdk extension to acquire a path to dotnet
   (instead of requiring a global installation accessible in the PATH)
 

resources/new-contract/java/build.gradle.template.txt

@@ -1,6 +1,6 @@
 plugins {
     id 'java'
-    id 'io.neow3j.gradle-plugin' version "3.8.0"
+    id 'io.neow3j.gradle-plugin' version "$_NEOW3JLIBVERSION_$"
 }
 
 group '$_REVERSEDOMAINNAME_$'
@@ -15,9 +15,9 @@ repositories {
 }
 
 dependencies {
-    implementation 'io.neow3j:contract:3.8.0'
-    implementation 'io.neow3j:devpack:3.8.0'
-    implementation 'io.neow3j:compiler:3.8.0'
+    implementation 'io.neow3j:contract:$_NEOW3JLIBVERSION_$'
+    implementation 'io.neow3j:devpack:$_NEOW3JLIBVERSION_$'
+    implementation 'io.neow3j:compiler:$_NEOW3JLIBVERSION_$'
     implementation 'junit:junit:4.12'
 }
 

src/extension/templates/languages.ts

@@ -1,3 +1,14 @@
+import tryFetchJson from "../util/tryFetchJson";
+
+// Variable resolution procedure:
+// i)   The `eval` function is called (if-present) and its result is used as the
+//      variable value.
+// ii)  If a `prompt` is provided the user is allowed to optionally specify a 
+//      value (which will overwrite the result of `eval`, if any)
+// iii) If a `parse` function is present it will be called and can modify the
+//      user-provided value.
+// After the above steps, the variable value must be non-empty or template hydration
+// will not proceed.
 type VariableDeclaration = {
   prompt?: string;
   eval?: (existingVariableValues: { [key: string]: string }) => Promise<string>;
@@ -94,6 +105,26 @@ const languages: { [code: string]: Language } = {
         eval: async ($) =>
           `src/main/java/${$["$_REVERSEDOMAINNAMEPATH_$"]}/${$["$_CLASSNAME_$"]}.java`,
       },
+      NEOW3JLIBVERSION: {
+        eval: async () => {
+          // Attempt to get the latest neow3j from Maven Central (falling back to
+          // a hard-coded version if Maven Central is not available or returns a
+          // malformed response):
+          const FALLBACK = "3.8.0";
+          const searchResults = await tryFetchJson(
+            "https",
+            "search.maven.org",
+            `/solrsearch/select?q=g:"io.neow3j"+AND+a:"core"`
+          );
+          return (
+            (searchResults.response?.docs || [])[0]?.latestVersion
+              ?.replace(/[^.a-z0-9]/gi, "")
+              ?.trim() || FALLBACK
+          );
+        },
+        prompt: "Which version of neow3j would you like to target?",
+        parse: (_) => Promise.resolve(_?.replace(/[^.a-z0-9]/gi, "").trim()),
+      },
     },
   },
 };

src/extension/templates/templates.ts

@@ -128,11 +128,15 @@ export default class Templates {
       for (const variableName of Object.keys(language.variables)) {
         const variable = language.variables[variableName];
         let value: string | undefined = "";
-        if (variable.prompt) {
-          value = await IoHelpers.enterString(variable.prompt);
-        } else if (variable.eval) {
+        if (variable.eval) {
           value = await variable.eval(result);
         }
+        if (variable.prompt) {
+          value = await IoHelpers.enterString(variable.prompt, value);
+        }
+        if (variable.parse) {
+          value = await variable.parse(value);
+        }
         if (!value) {
           // All variables are considered required
           return undefined;

src/extension/util/ioHelpers.ts

@@ -63,8 +63,11 @@ export default class IoHelpers {
     }
   }
 
-  static async enterString(prompt: string): Promise<string | undefined> {
-    return await vscode.window.showInputBox({ prompt });
+  static async enterString(
+    prompt: string,
+    value?: string
+  ): Promise<string | undefined> {
+    return await vscode.window.showInputBox({ prompt, value });
   }
 
   static async multipleChoice(placeHolder: string, ...items: string[]) {

src/extension/util/tryFetchJson.ts

@@ -0,0 +1,62 @@
+import * as wget from "wget-improved";
+
+import JSONC from "./JSONC";
+import Log from "../../shared/log";
+
+const LOG_PREFIX = "tryFetchJson";
+
+// Attempts to retrieve a URL using a HTTP GET request. Expects the server to respond with
+// a HTTP 200 status code and provide valid JSONC in the response body. Upon success, the
+// parsed JSONC object is returned. Upon failure, a warning is logged and an empty object
+// is returned.
+export default function tryFetchJson(
+  protocol: "https" | "http",
+  host: string,
+  path: string
+): any {
+  return new Promise((resolve) => {
+    const request = wget.request(
+      { host, method: "GET", path: encodeURI(path), protocol },
+      (response) => {
+        if (response.statusCode !== 200) {
+          Log.warn(
+            LOG_PREFIX,
+            `Got HTTP code ${response.statusCode} when attempting to download ${protocol}://${host}${path}`
+          );
+          resolve({});
+        } else {
+          let content = "";
+          response.on("error", (err) => {
+            Log.warn(
+              LOG_PREFIX,
+              `Error ("${err}") when processing response from ${protocol}://${host}${path}`
+            );
+            resolve({});
+          });
+          response.on("data", (data) => {
+            content = content + data;
+          });
+          response.on("end", () => {
+            try {
+              resolve(JSONC.parse(content));
+            } catch (e) {
+              Log.warn(
+                LOG_PREFIX,
+                `Exception ("${e}") when parsing JSON from ${protocol}://${host}${path}`
+              );
+              resolve({});
+            }
+          });
+        }
+      }
+    );
+    request.on("error", (err) => {
+      Log.warn(
+        LOG_PREFIX,
+        `Error ("${err}") when sending request to ${protocol}://${host}${path}`
+      );
+      resolve({});
+    });
+    request.end();
+  });
+}