BeanLookupBindings for simpler script access to beans

The new class BeanLookupBindings allows scripts to skip getBean calls.
Lines like 'beanname = appCtx.getBean("beanname")' can be left out.
Past scripts remain compatible.
This change effects action directory scripts and rest console scripts.

engine/src/main/java/org/archive/crawler/framework/ActionDirectory.java

@@ -31,6 +31,7 @@ import java.util.concurrent.TimeUnit;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
+import javax.script.Bindings;
 import javax.script.ScriptEngine;
 import javax.script.ScriptEngineManager;
 import javax.script.ScriptException;
@@ -311,22 +312,20 @@ public class ActionDirectory implements ApplicationContextAware, Lifecycle, Runn
         StringWriter rawString = new StringWriter(); 
         PrintWriter rawOut = new PrintWriter(rawString);
         Exception ex = null;
-        engine.put("rawOut", rawOut);
-        engine.put("appCtx", appCtx);
+        Bindings bindings = new BeanLookupBindings(appCtx);
+        bindings.put("rawOut", rawOut);
+        bindings.put("appCtx", appCtx);
         
         // evaluate and record any exception
         try {
             String script = FileUtils.readFileToString(actionFile);
-            engine.eval(script);
+            engine.eval(script, bindings);
         } catch (IOException e) {
             ex = e;
         } catch (ScriptException e) {
             ex = e;
         } catch (RuntimeException e) {
             ex = e;
-        } finally {
-            engine.put("rawOut", null);
-            engine.put("appCtx", null);
         }
 
         // report output/exception to files paired with script in done dir

engine/src/main/java/org/archive/crawler/framework/BeanLookupBindings.java

@@ -0,0 +1,66 @@
+package org.archive.crawler.framework;
+
+import java.util.Map;
+
+import javax.script.SimpleBindings;
+
+import org.springframework.beans.BeansException;
+import org.springframework.context.ApplicationContext;
+
+/**
+ * Provides syntactic sugar for H3 scripts to reference beans without adding a
+ * line like {@code def scope = appCtx.getBean("scope");}. Instead, the script
+ * may simply reference {@code scope}. Caveat: access is read only.
+ * 
+ * @contributor travis
+ */
+public class BeanLookupBindings extends SimpleBindings {
+
+    private ApplicationContext appCtx = null;
+
+    public BeanLookupBindings(ApplicationContext appCtx) {
+        assert appCtx != null;
+        this.appCtx = appCtx;
+    }
+
+    public BeanLookupBindings(ApplicationContext appCtx, Map<String, Object> m) {
+        super(m);
+        assert appCtx != null;
+        this.appCtx = appCtx;
+    }
+
+    @Override
+    public Object get(Object key) {
+        if (key instanceof String) {
+            try {
+                Object ret = appCtx.getBean((String) key);
+                if (ret != null) {
+                    return ret;
+                }
+            } catch (BeansException e) {}
+        }
+        return super.get(key);
+    }
+
+    @Override
+    public boolean containsKey(Object key) {
+        if (key instanceof String) {
+            try {
+                boolean ret = appCtx.containsBean((String) key);
+                if (ret == true) {
+                    return ret;
+                }
+            } catch (BeansException e) {}
+        }
+        return super.containsKey(key);
+    }
+
+    @Override
+    public Object put(String name, Object value) {
+        // restrict setting variables that conflict with bean names
+        if (appCtx.containsBean(name)) {
+            throw new IllegalArgumentException("name conflict: \""+ name +"\" is the name of a bean.");
+        }
+        return super.put(name, value);
+    }
+}

engine/src/main/java/org/archive/crawler/restlet/ScriptResource.java

@@ -31,6 +31,7 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 
+import javax.script.Bindings;
 import javax.script.ScriptEngine;
 import javax.script.ScriptEngineFactory;
 import javax.script.ScriptEngineManager;
@@ -38,6 +39,7 @@ import javax.script.ScriptException;
 
 import org.apache.commons.lang.StringEscapeUtils;
 import org.apache.commons.lang.StringUtils;
+import org.archive.crawler.framework.BeanLookupBindings;
 import org.archive.util.TextUtils;
 import org.restlet.Context;
 import org.restlet.data.CharacterSet;
@@ -50,6 +52,7 @@ import org.restlet.resource.Representation;
 import org.restlet.resource.ResourceException;
 import org.restlet.resource.Variant;
 import org.restlet.resource.WriterRepresentation;
+import org.springframework.context.ApplicationContext;
 
 /**
  * Restlet Resource which runs an arbitrary script, which is supplied
@@ -102,13 +105,15 @@ public class ScriptResource extends JobRelatedResource {
         
         StringWriter rawString = new StringWriter(); 
         PrintWriter rawOut = new PrintWriter(rawString);
+        ApplicationContext appCtx = cj.getJobContext();
+        Bindings bindings = new BeanLookupBindings(appCtx);
         eng.put("rawOut", rawOut);
         StringWriter htmlString = new StringWriter(); 
         PrintWriter htmlOut = new PrintWriter(htmlString);
-        eng.put("htmlOut", htmlOut);
-        eng.put("job", cj);
-        eng.put("appCtx", cj.getJobContext());
-        eng.put("scriptResource", this);
+        bindings.put("htmlOut", htmlOut);
+        bindings.put("job", cj);
+        bindings.put("appCtx", appCtx);
+        bindings.put("scriptResource", this);
         try {
             eng.eval(script);
             linesExecuted = script.split("\r?\n").length;
@@ -121,12 +126,6 @@ public class ScriptResource extends JobRelatedResource {
             rawOutput = rawString.toString();
             htmlOut.flush();
             htmlOutput = htmlString.toString();
-
-            eng.put("rawOut", null);
-            eng.put("htmlOut", null);
-            eng.put("job", null);
-            eng.put("appCtx", null);
-            eng.put("scriptResource", null);
         }
         //TODO: log script, results somewhere; job log INFO?