feat: implementation of TS common viewContent, URL fragment & remote …

…URL content (#2841)

* feat: initial implementation of TS viewContent & URL fragment.
- Add view content processing, to inject common view content
  when a view is loaded.
- Add URL hash/fragment location when loading the view.
* fix: getStyle instead of getTokenView
* fix: Add minimum TS schema version to support old versions
This allows adding new features to future schema versions
whilst maintaining backward compatibility with old schemas.

It adds a new static variable TOKENSCRIPT_MINIMUM_SCHEMA and
function isSchemaLessThanMinimum. This it then used to determine
if old definitions should be deleted. Old versions are now only
deleted if they don't meet the minimum, rather than not matching
the TOKENSCRIPT_CURRENT_SCHEMA.

* fix: namespace null check
* feat: TS - Add URL attribute functionality to load remote views

This change allows TokenScripts to use the url attribute of a view to
specify that the view should be loaded from a remote location such as IPFS.
For bigger applications, it becomes hard for the developer to embed all required
assets inside a small TokenScript; such as fonts, large graphics and other media.

This provides a different route that make it easier to make richer applications
while ensuring TokenScript TSML size remains small. It also demonstrates the
potential for existing DApps to be easily ported to TokenScript, provided
that Web3TokenView.java is updated to provide the full ethereum provider to the client.
Access to the full provider can be specified as a TokenScript view attribute,
adding an extra layer of security.

app/src/main/java/com/alphawallet/app/service/AssetDefinitionService.java

@@ -391,7 +391,7 @@ private TokenDefinition fileLoadComplete(List<ContractLocator> originContracts,
         try (Realm realm = realmManager.getRealmInstance(ASSET_DEFINITION_DB))
         {
             //check for out-of-date script in the secure (downloaded) zone
-            if (isInSecureZone(file) && !td.nameSpace.equals(TokenDefinition.TOKENSCRIPT_NAMESPACE))
+            if (isInSecureZone(file) && td.isSchemaLessThanMinimum())
             {
                 //delete this file and check downloads for update
                 removeFile(file.getAbsolutePath());
@@ -1409,7 +1409,7 @@ private Single<File> fetchXMLFromServer(String address)
             if (result != null && result.exists())
             {
                 TokenDefinition td = getTokenDefinition(result);
-                if (definitionIsOutOfDate(td))
+                if (td.isSchemaLessThanMinimum())
                 {
                     removeFile(result.getAbsolutePath());
                     assetChecked.put(address, 0L);
@@ -1498,11 +1498,6 @@ private String[] getHeaders(long currentFileTime) throws PackageManager.NameNotF
         };
     }
 
-    private boolean definitionIsOutOfDate(TokenDefinition td)
-    {
-        return td != null && !td.nameSpace.equals(TokenDefinition.TOKENSCRIPT_NAMESPACE);
-    }
-
     private void finishLoading()
     {
         assetLoadingLock.release();

app/src/main/java/com/alphawallet/app/ui/FunctionActivity.java

@@ -78,6 +78,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 import dagger.hilt.android.AndroidEntryPoint;
 import io.reactivex.android.schedulers.AndroidSchedulers;
@@ -166,12 +167,17 @@ private void displayFunction(String tokenAttrs)
             TSAction action = functions.get(actionMethod);
             String magicValues = viewModel.getAssetDefinitionService().getMagicValuesForInjection(token.tokenInfo.chainId);
 
-            String injectedView = tokenView.injectWeb3TokenInit(action.view.tokenView, tokenAttrs, tokenId);
-            injectedView = tokenView.injectJSAtEnd(injectedView, magicValues);
-            injectedView = tokenView.injectStyleAndWrapper(injectedView, action.style + "\n" + action.view.style);
-
-            String base64 = Base64.encodeToString(injectedView.getBytes(StandardCharsets.UTF_8), Base64.DEFAULT);
-            tokenView.loadData(base64, "text/html; charset=utf-8", "base64");
+            if (Objects.equals(action.view.getUrl(), ""))
+            {
+                String injectedView = tokenView.injectWeb3TokenInit(action.view.getTokenView(), tokenAttrs, tokenId);
+                injectedView = tokenView.injectJSAtEnd(injectedView, magicValues);
+                injectedView = tokenView.injectStyleAndWrapper(injectedView, action.style + "\n" + action.view.getStyle());
+
+                String base64 = Base64.encodeToString(injectedView.getBytes(StandardCharsets.UTF_8), Base64.DEFAULT);
+                tokenView.loadData(base64 + (!Objects.equals(action.view.getUrlFragment(), "") ? "#" + action.view.getUrlFragment() : ""), "text/html; charset=utf-8", "base64");
+            } else {
+                tokenView.loadUrl(action.view.getUrl());
+            }
         }
         catch (Exception e)
         {

app/src/main/java/com/alphawallet/app/ui/widget/holder/EventHolder.java

@@ -100,7 +100,7 @@ public void bind(@Nullable EventMeta data, @NonNull Bundle addition)
         if (td != null && td.getActivityCards().containsKey(eventData.getFunctionId()))
         {
             TSTokenView view = td.getActivityCards().get(eventData.getFunctionId()).getView(ASSET_SUMMARY_VIEW_NAME);
-            if (view != null) itemView = view.tokenView;
+            if (view != null) itemView = view.getTokenView();
         }
 
         String transactionValue = getEventAmount(eventData, transaction);

app/src/main/java/com/alphawallet/app/ui/widget/holder/TransferHolder.java

@@ -138,7 +138,7 @@ private void bindView(TokenTransferData data, Transaction tx)
         if (td != null && td.getActivityCards().containsKey(data.eventName))
         {
             TSTokenView view = td.getActivityCards().get(data.eventName).getView(ASSET_SUMMARY_VIEW_NAME);
-            if (view != null) itemView = view.tokenView;
+            if (view != null) itemView = view.getTokenView();
         }
 
         String transactionValue = transferData.getEventAmount(token, tx);

app/src/test/java/com/alphawallet/app/tokenscript/TokenscriptFunctionTest.java

@@ -14,6 +14,7 @@
 import java.util.Locale;
 
 import static com.alphawallet.token.tools.TokenDefinition.TOKENSCRIPT_CURRENT_SCHEMA;
+import static com.alphawallet.token.tools.TokenDefinition.TOKENSCRIPT_MINIMUM_SCHEMA;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
@@ -550,8 +551,8 @@ public void testHoldingToken() {
 
     @Test
     public void entryTokenNameSpaceShouldBeCorrect() {
-        String currentNamespace = "http://tokenscript.org/" + TOKENSCRIPT_CURRENT_SCHEMA + "/tokenscript";
-        assertTrue("should match the latest namespace", entryToken.nameSpace.equals(currentNamespace));
+        String currentNamespace = "http://tokenscript.org/" + TOKENSCRIPT_MINIMUM_SCHEMA + "/tokenscript";
+        assertTrue("should match the minimum namespace", entryToken.nameSpace.equals(currentNamespace));
     }
 
     @Override
@@ -575,4 +576,4 @@ public void parseMessage(ParseResultId parseResult)
                 break;
         }
     }
-}
+}

lib/src/main/java/com/alphawallet/token/entity/TSTokenView.java

@@ -7,18 +7,37 @@
 import static org.w3c.dom.Node.ELEMENT_NODE;
 import static org.w3c.dom.Node.TEXT_NODE;
 
+import com.alphawallet.token.tools.TokenDefinition;
+
+import java.util.Objects;
+
 /**
  * Holds an individual Token View which consists of style and HTML view code
  *
  * Created by JB on 8/05/2020.
  */
 public class TSTokenView
 {
-    public final String tokenView;
-    public final String style;
+    private String tokenView = "";
+    private String style = "";
+
+    private Element element;
+    private TokenDefinition tokenDef;
+
+    public TSTokenView(Element element, TokenDefinition tokenDef)
+    {
+        this.element = element;
+        this.tokenDef = tokenDef;
+    }
 
-    public TSTokenView(Element element)
+    private void generateTokenView(Element element)
     {
+
+        if (!Objects.equals(this.getUrl(), ""))
+        {
+            return;
+        }
+
         String lStyle = "";
         String lView = "";
         for (int i = 0; i < element.getChildNodes().getLength(); i++)
@@ -34,6 +53,11 @@ public TSTokenView(Element element)
                             //record the style for this
                             lStyle += getHTMLContent(child);
                             break;
+                        case "viewContent":
+                            String name = child.getAttributes().getNamedItem("name").getTextContent();
+                            Element content = this.tokenDef.getViewContent(name);
+                            generateTokenView(content);
+                            break;
                         default:
                             lView += getElementHTML(child);
                             break;
@@ -51,8 +75,38 @@ public TSTokenView(Element element)
             }
         }
 
-        tokenView = lView;
-        style = lStyle;
+        tokenView += lView;
+        style += lStyle;
+    }
+
+    public String getTokenView()
+    {
+        if (tokenView.isEmpty())
+        {
+            generateTokenView(this.element);
+        }
+
+        return tokenView;
+    }
+
+    public String getStyle()
+    {
+        if (style.isEmpty())
+        {
+            generateTokenView(this.element);
+        }
+
+        return style;
+    }
+
+    public String getUrl()
+    {
+        return this.element.getAttribute("url");
+    }
+
+    public String getUrlFragment()
+    {
+        return this.element.getAttribute("urlFragment");
     }
 
     public TSTokenView(String style, String view)

lib/src/main/java/com/alphawallet/token/entity/TSTokenViewHolder.java

@@ -17,7 +17,7 @@ public String getView(String viewName)
         TSTokenView v = views.get(viewName);
         if (v != null)
         {
-            return v.tokenView;
+            return v.getTokenView();
         }
         else
         {
@@ -28,6 +28,6 @@ public String getView(String viewName)
     public String getViewStyle(String viewName)
     {
         TSTokenView v = views.get(viewName);
-        return (globalStyle != null ? globalStyle : "") + (v != null ? v.style : "");
+        return (globalStyle != null ? globalStyle : "") + (v != null ? v.getStyle() : "");
     }
 }

lib/src/main/java/com/alphawallet/token/tools/TokenDefinition.java

@@ -72,13 +72,15 @@ public class TokenDefinition
     private final TSTokenViewHolder tokenViews = new TSTokenViewHolder();
     private final Map<String, TSSelection> selections = new HashMap<>();
     private final Map<String, TSActivityView> activityCards = new HashMap<>();
+    private final Map<String, Element> viewContent = new HashMap<>();
 
     public String nameSpace;
     public TokenscriptContext context;
     public String holdingToken = null;
     private int actionCount;
 
-    public static final String TOKENSCRIPT_CURRENT_SCHEMA = "2020/06";
+    public static final String TOKENSCRIPT_MINIMUM_SCHEMA = "2020/06";
+    public static final String TOKENSCRIPT_CURRENT_SCHEMA = "2022/09";
     public static final String TOKENSCRIPT_REPO_SERVER = "https://repo.tokenscript.org/";
     public static final String TOKENSCRIPT_NAMESPACE = "http://tokenscript.org/" + TOKENSCRIPT_CURRENT_SCHEMA + "/tokenscript";
 
@@ -615,11 +617,19 @@ private void handleCards(Element cards) throws Exception
                     case "card":
                         extractCard(card);
                         break;
+                    case "viewContent":
+                        this.viewContent.put(card.getAttribute("name"), card);
+                        break;
                 }
             }
         }
     }
 
+    public Element getViewContent(String name)
+    {
+        return this.viewContent.get(name);
+    }
+
     private TSActivityView processActivityView(Element card) throws Exception
     {
         NodeList ll = card.getChildNodes();
@@ -641,7 +651,7 @@ private TSActivityView processActivityView(Element card) throws Exception
                 case "view": //TODO: Localisation
                 case "item-view":
                     if (activityView == null) throw new SAXException("Activity card declared without origins tag");
-                    activityView.addView(node.getLocalName(), new TSTokenView(element));
+                    activityView.addView(node.getLocalName(), new TSTokenView(element, this));
                     break;
                 default:
                     throw new SAXException("Unknown tag <" + node.getLocalName() + "> tag in tokens");
@@ -670,7 +680,7 @@ private void processTokenCardElements(Element card) throws Exception
                     break;
                 case "view": //TODO: Localisation
                 case "item-view":
-                    TSTokenView v = new TSTokenView(element);
+                    TSTokenView v = new TSTokenView(element, this);
                     tokenViews.views.put(node.getLocalName(), v);
                     break;
                 case "view-iconified":
@@ -767,6 +777,35 @@ else if (thisDate.before(schemaDate))
         }
     }
 
+    public boolean isSchemaLessThanMinimum()
+    {
+
+        if (nameSpace == null)
+        {
+            return true;
+        }
+
+        int dateIndex = nameSpace.indexOf(TOKENSCRIPT_BASE_URL) + TOKENSCRIPT_BASE_URL.length();
+        int lastSeparator = nameSpace.lastIndexOf("/");
+        if ((lastSeparator - dateIndex) == 7)
+        {
+            try
+            {
+                DateFormat format = new SimpleDateFormat("yyyy/MM", Locale.ENGLISH);
+                Date thisDate = format.parse(nameSpace.substring(dateIndex, lastSeparator));
+                Date schemaDate = format.parse(TOKENSCRIPT_MINIMUM_SCHEMA);
+
+                return thisDate.before(schemaDate);
+            }
+            catch (Exception e)
+            {
+                return true;
+            }
+        }
+
+        return true;
+    }
+
     private void extractCard(Element card) throws Exception
     {
         TSAction action;
@@ -848,7 +887,7 @@ private TSAction handleAction(Element action) throws Exception
                 case "selection":
                     throw new SAXException("<ts:selection> tag must be in main scope (eg same as <ts:origins>)");
                 case "view": //localised?
-                    tsAction.view = new TSTokenView(element);
+                    tsAction.view = new TSTokenView(element, this);
                     break;
                 case "style":
                     tsAction.style = getHTMLContent(element);
@@ -1686,8 +1725,8 @@ public String getCardData(String tag)
     {
         TSTokenView view = tokenViews.views.get("view");
 
-        if (tag.equals("view")) return view.tokenView;
-        else if (tag.equals("style")) return view.style;
+        if (tag.equals("view")) return view.getTokenView();
+        else if (tag.equals("style")) return view.getStyle();
         else return null;
     }