feat(plugins) Add first pass OHIFPlugin class for experimentation

Packages/ohif-viewerbase/client/index.js

@@ -227,6 +227,9 @@ import { InstanceMetadata } from './lib/classes/metadata/InstanceMetadata';
 import { StudySummary } from './lib/classes/metadata/StudySummary';
 Viewerbase.metadata = { StudyMetadata, SeriesMetadata, InstanceMetadata, StudySummary };
 
+import { OHIFPlugin } from './lib/classes/OHIFPlugin';
+Viewerbase.OHIFPlugin = OHIFPlugin;
+
 // TypeSafeCollection
 import { TypeSafeCollection } from './lib/classes/TypeSafeCollection';
 Viewerbase.TypeSafeCollection = TypeSafeCollection;

Packages/ohif-viewerbase/client/lib/classes/OHIFPlugin.js

@@ -0,0 +1,56 @@
+// TODO: Add plugin reloader
+class OHIFPlugin {
+    // TODO: this class is still under development and will
+    // likely change in the near future
+    constructor () {
+        this.name = "Unnamed plugin";
+        this.description = "No description available";
+    }
+
+    // load an individual script URL
+    static loadScript(scriptURL) {
+        const script = document.createElement("script");
+
+        script.src = scriptURL;
+        script.type = "text/javascript";
+        script.async = false;
+
+        const head = document.getElementsByTagName("head")[0];
+        head.appendChild(script);
+        head.removeChild(script);
+
+        return script;
+    }
+
+    // reload all the dependency scripts and also
+    // the main plugin script url.
+    static reloadPlugin(plugin) {
+        plugin.scriptURLs = plugin.scriptURLs || {};
+        plugin.scriptURLs.forEach(scriptURL => {
+            this.loadScript(scriptURL).onload = function() {}
+        });
+
+        let scriptURL = plugin.url;
+
+        if (plugin.allowCaching === false) {
+            scriptURL += "?" + performance.now();
+        }
+
+        this.loadScript(scriptURL).onload = function() {
+            if (OHIFPlugin.entryPoints[plugin.name]) {
+                OHIFPlugin.entryPoints[plugin.name]();
+            }
+        }
+    }
+}
+
+// each plugin registers an entry point function to be called
+// when the loading is complete (called above in reloadPlugin).
+
+// TODO: Move to OHIF.plugins.entryPoints?
+OHIFPlugin.entryPoints = {};
+
+export { OHIFPlugin };
+
+// TODO: Should we remove this? Authors should be able to use new 'OHIF.viewerbase.OHIFPlugin()'
+window.OHIFPlugin = OHIFPlugin;