Hokosugi req

README.md

@@ -32,7 +32,7 @@ dfx start --background
 dfx deploy
 ```
 
-Once the job completes, your application will be available at `http://localhost:8000?canisterId={asset_canister_id}`.
+Once the job completes, your application will be available at `http://localhost:8030?canisterId={asset_canister_id}`.
 
 Additionally, if you are making frontend changes, you can start a development server with
 

dfx.json

@@ -3,6 +3,19 @@
     "small_nft": {
       "main": "src/small_nft/main.mo",
       "type": "motoko"
+    },
+    "small_nft_assets": {
+      "dependencies": [
+        "small_nft"
+      ],
+      "frontend": {
+        "entrypoint": "src/small_nft_assets/src/index.html"
+      },
+      "source": [
+        "src/small_nft_assets/assets",
+        "dist/small_nft_assets/"
+      ],
+      "type": "assets"
     }
   },
   "defaults": {
@@ -14,7 +27,7 @@
   "dfx": "0.8.1",
   "networks": {
     "local": {
-      "bind": "127.0.0.1:8000",
+      "bind": "127.0.0.1:8030",
       "type": "ephemeral"
     }
   },

package.json

@@ -2,7 +2,12 @@
   "name": "small_nft_assets",
   "version": "0.1.0",
   "description": "Internet Computer starter application",
-  "keywords": ["Internet Computer", "Motoko", "JavaScript", "Canister"],
+  "keywords": [
+    "Internet Computer",
+    "Motoko",
+    "JavaScript",
+    "Canister"
+  ],
   "scripts": {
     "build": "webpack",
     "prebuild": "npm run copy:types",
@@ -23,9 +28,9 @@
     "stream-browserify": "3.0.0",
     "terser-webpack-plugin": "5.1.1",
     "util": "0.12.3",
-    "webpack-cli": "4.5.0",
-    "webpack-dev-server": "^3.11.2",
-    "webpack": "5.24.4"
+    "webpack": "5.24.4",
+    "webpack-cli": "^4.9.0",
+    "webpack-dev-server": "^3.11.3"
   },
   "browserslist": [
     "last 2 chrome version",

src/small_nft/main.mo

@@ -14,6 +14,8 @@ import Nat "mo:base/Nat";               //  HashMapの第2引数で使用
 import Hash "mo:base/Hash";             //  HashMapの第3引数で使用
 import Iter "mo:base/Iter";             //  preupgrade,postupgradeで使う．HashMapのエントリを書き出す．
 
+ //  エラー処理用のモジュール（add:by hokosugi）              
+import Result "mo:base/Result";
 
 //  `shared(<変数名>)`を加えることで，ICProtocolからこのトランザクションの呼び出し人を受け取ることができる．
 //  `<変数名>.caller`でそのPrincipalを参照できる．
@@ -57,6 +59,18 @@ shared(installer) actor class Small_NFT() {
     private var _tokenRegistry = HashMap.HashMap<TokenID, TokenInfo>(1, Nat.equal, Hash.hash);
     private stable var _latestTokenID: Nat = 0;
 
+    //④ エラー処理(add: by hokosugi)
+    //  Resultライブラリから型指定(https://smartcontracts.org/docs/base-libraries/Result.html)
+    public type Errors = {
+        #notFoundTokenInfo;
+        #alreadyExist;              // 未使用
+    };
+    // okの時で関数内で別の型がある時に使う.
+    public type Okays = {
+        #canTransfer : Text;
+        #IsSuccess : Nat;
+    };
+
 
     public shared(msg) func mint(to : Principal, metadata : ?TokenMetadata) : async TokenID{
         //  最新のtokeIDの更新
@@ -75,7 +89,8 @@ shared(installer) actor class Small_NFT() {
         return _latestTokenID;
     };
 
-    public query func ownerOf(tokenId : TokenID) : async Text {   //public funcの戻り値はasync型として記述
+
+    public query func ownerOf(tokenId : TokenID) : async Result.Result<Text, Errors> {   //public funcの戻り値はasync型として記述
         //  このswitch-case文がmotokoの鬼門
         /*
         HashMapはnull許容型として帰ってくるため，型安全性のため一度Nullを場合分けしなくてはならない．
@@ -86,33 +101,33 @@ shared(installer) actor class Small_NFT() {
         switch(_tokenRegistry.get(tokenId)) {
             case(?tokenInfo) {
                 //owner
-                return Principal.toText(tokenInfo.owner);
+                return #ok(Principal.toText(tokenInfo.owner));
             };
             case(_){
-                return "none";
+                return #err(#notFoundTokenInfo);
             };
         };  
     };
 
-    public shared(msg) func transfer(to : Principal, tokenId : TokenID) : async TokenID {
+    public shared(msg) func transfer(to : Principal, tokenId : TokenID) : async Result.Result<Okays, Errors> {
         switch(_tokenRegistry.get(tokenId)) {
             case(?tokenInfo) {
                 if(tokenInfo.owner != msg.caller ) {
-                    return 0;
+                    return #ok(#canTransfer("yes"));
                 };
 
                 //ownerの書き換え
                 tokenInfo.owner := to; // switch-caseは参照渡しなので，これで直接代入できるはず．
-                return tokenId;
+                return #ok(#IsSuccess(tokenId));
             };
             case(_){
-                return 0;
+                return #err(#notFoundTokenInfo);
             };
         };
     };
 
-    public query func latestTokenID() : async TokenID {
-        return  _latestTokenID;
+    public query func latestTokenID() : async Result.Result<Nat, Text> {
+        return  #ok(_latestTokenID);
     };
 
     //State functions