o Tried to improve error handling when the backend server fails.HEADmaster

2 files changed, 144 insertions, 49 deletions

diff --git a/src/main/scala/io/trygvis/cj/Explorer.scala b/src/main/scala/io/trygvis/cj/Explorer.scala
index 9c4206f..5089d1f 100644
--- a/src/main/scala/io/trygvis/cj/Explorer.scala
+++ b/src/main/scala/io/trygvis/cj/Explorer.scala
@@ -1,8 +1,10 @@
 package io.trygvis.cj
 
 import scala.collection.JavaConversions._
+import scala.util.Properties
+import scala.util.control.Exception._
 import scala.io.Source
-import java.net.{URLEncoder, HttpURLConnection, URI}
+import java.net.{URL, URLEncoder, HttpURLConnection, URI}
 import java.io._
 import javax.servlet.http.HttpServletRequest
 import unfiltered.request._
@@ -10,7 +12,8 @@ import unfiltered.response._
 import unfiltered.filter._
 import unfiltered.jetty._
 
-case class CjResponse(code: Int, status: String, headers: java.util.Map[String, java.util.List[String]])
+case class CjRequest(urlString: String, url: Option[URL], method: String, headers: Option[Map[String, java.util.List[String]]])
+case class CjResponse(code: Int, status: String, headers: java.util.Map[String, java.util.List[String]], content: Option[String])
 
 class Browser extends Plan {
   import unfiltered.directives._, Directives._
@@ -26,7 +29,8 @@ class Browser extends Plan {
     new Views(uri)
   }
 
-  def queryParam(name: String) = Directive[Any, Any, String]({ request: HttpRequest[Any] =>
+  def queryParam(name: String) = Directive[Any, Any, String]({
+    request: HttpRequest[Any] =>
       request.parameterValues(name).headOption match {
         case Some(value) =>
           Result.Success(value)
@@ -51,9 +55,10 @@ class Browser extends Plan {
           params <- QueryParams
           views = viewsX(r)
         } yield {
-          println("url=" + url)
+          val method = Option(r.getParameter("method")).filter {_.nonEmpty} getOrElse "GET"
+          println("Request: " + method + " " + url)
 
-          val targetParams = params flatMap {
+          val collectionParams = params flatMap {
             case (key, value) if key.startsWith("param-") =>
               // It makes no sense to have duplicate query keys so just pick the first one. This is most likely the
               // same as most web framework does when given multiple query parameters.
@@ -62,30 +67,52 @@ class Browser extends Plan {
               None
           }
 
-          println("targetParam=" + targetParams)
+          val q = collectionParams map {
+            case (key, value) =>
+              URLEncoder.encode(key, "utf-8") + "=" + URLEncoder.encode(value, "utf-8")
+          }
+
+          val collectionUrlString = url + (if (q.nonEmpty) "?" + q.reduce(_ ++ "&" ++ _) else "")
+          val collectionUrl = allCatch opt {URI.create(collectionUrlString).toURL } filter {_.getProtocol.startsWith("http")}
 
-          val q = targetParams map { case (key, value) =>
-            URLEncoder.encode(key, "utf-8") + "=" + URLEncoder.encode(value, "utf-8")
+          val conO = collectionUrl map { u: java.net.URL =>
+            val c = u.openConnection().asInstanceOf[HttpURLConnection]
+            c.setRequestProperty("Accept", "application/vnd.collection+json")
+            c.setUseCaches(false)
+            c
           }
 
-          println("q=" + q)
+          val response = conO map { c => allCatch either {
+            c.connect()
+            val headers = c.getHeaderFields.toMap filter { case (key, value) => key != null }
+            val content = allCatch opt Source.fromInputStream(c.getInputStream, "utf-8").mkString("")
+
+            c.disconnect()
+
+            CjResponse(c.getResponseCode, c.getResponseMessage, headers, content)
+          }}
 
-          val uri = URI.create(url + (if(q.nonEmpty) "?" + q.reduce (_ ++ "&" ++ _) else ""))
-          println("uri=" + uri)
+          val requestHeaders = conO map { con =>
+            con.getRequestProperties.toMap filter { case (key, value) => !value.isEmpty && value.get(0) != null }
+          }
+
+          val collection = response match {
+            case Some(Right(CjResponse(_, _, _, Some(content)))) =>
+              Some(Collection.parseCollection(new StringReader(content)))
+            case _ => None
+          }
 
-          val con = uri.toURL.openConnection().asInstanceOf[HttpURLConnection]
-          con.setRequestProperty("accept", "application/vnd.collection+json")
-          val content = Source.fromInputStream(con.getInputStream, "utf-8").mkString("")
-          val headers = con.getHeaderFields.toMap filter {case (key, _) => key != null}
-          val result = Collection.parseCollection(new StringReader(content))
-          Ok ~> Html5(views.data(uri, targetParams, result, CjResponse(con.getResponseCode, con.getResponseMessage, headers)))
+          Ok ~> Html5(views.data(CjRequest(collectionUrlString, collectionUrl, method, requestHeaders), response, collectionParams, collection))
         }
     }
   }
 }
 
 object Explorer extends App {
-  Http(8080).
+  val port = Properties.envOrElse("PORT", "8080").toInt
+  println("Starting on port:" + port)
+
+  Http(port).
     plan(new Browser).
     resources(getClass.getResource("/public/")).
     run()
diff --git a/src/main/scala/io/trygvis/cj/Views.scala b/src/main/scala/io/trygvis/cj/Views.scala
index b4429d8..8b3e5d9 100644
--- a/src/main/scala/io/trygvis/cj/Views.scala
+++ b/src/main/scala/io/trygvis/cj/Views.scala
@@ -1,10 +1,12 @@
 package io.trygvis.cj
 
 import scala.collection.JavaConversions._
-import scala.xml.{Group, NodeSeq, Elem}
-import java.net.{MalformedURLException, URL, URI, URLEncoder}
+import scala.xml.{NodeSeq, Elem}
+import java.net._
 import org.json4s.native.JsonMethods
 import java.io.{PrintWriter, StringWriter, Writer}
+import scala.xml.Group
+import scala.Some
 
 class Views(baseUrl: String) {
 
@@ -120,8 +122,8 @@ class Views(baseUrl: String) {
     layout(content, None)
   }
 
-  def data(url: URI, targetParams: Map[String, String], result: Either[Throwable, Collection], res: CjResponse) = {
-
+  def data(request: CjRequest, response: Option[Either[Throwable, CjResponse]],
+           targetParams: Map[String, String], collection: Option[Either[Throwable, Collection]]) = {
     def href(uri: URI) = {
 //      val splits = uri.getPath.split('/')
 //      for split in splits
@@ -413,26 +415,66 @@ class Views(baseUrl: String) {
       </div>
     }
 
-    def httpResponse = {
+    def httpRequest(req: CjRequest) = {
       <div class="row-fluid">
-        <dl>
-          <dt>Request URL</dt>
-          <dd><a href={render(url)}>{url}</a></dd>
-        </dl>
-        <table>
-          <tr>
-            <td colspan="2">{res.code} {res.status}</td>
-          </tr>
-          {res.headers map { case (header, values) => { values map { value =>
-            <tr>
-              <td><tt>{header}</tt></td>
-              <td><tt>{tryLink(value)}</tt></td>
-            </tr>
-          }}}}
-        </table>
+        {req.url match {
+          case None =>
+            <dl>
+              <dt>Could not parse generated URL</dt>
+              <dd>{req.urlString}</dd>
+            </dl>
+          case _ =>
+        }}
+        {
+        req.headers match {
+          case None =>
+          case Some(headers) =>
+            <h2>Request</h2>
+            <table>
+              <tr>
+                <td colspan="2"><tt>{req.method} {req.url map { url => <a href={render(url.toURI)}>{url.toExternalForm}</a> } getOrElse req.urlString}</tt></td>
+              </tr>
+              {headers map { case (header, values) => { values map { value =>
+              <tr>
+                <td><tt>{header}: </tt></td>
+                <td><tt>{tryLink(value)}</tt></td>
+              </tr>
+            }}}}
+            </table>
+        }}
       </div>
     }
 
+    def httpResponse(r: Either[Throwable, CjResponse]) = { r match {
+      case Left(ex) =>
+        if (ex.isInstanceOf[ConnectException]) {
+          "Unable to connect: " + ex.getMessage
+        } else if (ex.isInstanceOf[UnknownHostException]) {
+          "Unknown host: " + ex.getMessage
+        } else {
+          <xml:group>
+          <p>Unknown error while connecting to remote server</p>
+          <pre>{getStackTrace(ex)}</pre>
+          </xml:group>
+        }
+      case Right(res) =>
+        <div class="row-fluid">
+          <tt>
+          <table>
+            <tr>
+              <td colspan="2">{res.code} {res.status}</td>
+            </tr>
+            {res.headers map { case (header, values) => { values map { value =>
+              <tr>
+                <td>{header}: </td>
+                <td>{tryLink(value)}</td>
+              </tr>
+            }}}}
+          </table>
+          </tt>
+        </div>
+    }}
+
     def parsedContent(implicit cj: Collection) = <xml:group>
       <section id="meta">
         <div class="page-header">
@@ -477,13 +519,14 @@ class Views(baseUrl: String) {
     </xml:group>
 
     def innerContent = <xml:group>
-      {result match {
-        case Left(ex) =>
+      {collection match {
+        case None =>
+        case Some(Left(ex)) =>
           <section id="server-error">
             <div class="page-header"><h1>Server Error</h1></div>
             <pre>{getStackTrace(ex)}</pre>
           </section>
-        case Right(cj) => <xml:group>
+        case Some(Right(cj)) => <xml:group>
           {try { parsedContent(cj) } catch { case ex: Exception => <div>Unable to process model: {ex.getMessage}</div> }}
           <section id="formatted-body">
             <div class="page-header"><h1>Formatted Body</h1></div>
@@ -495,23 +538,32 @@ class Views(baseUrl: String) {
           </section>
         </xml:group>
       }}
-      <section id="http-response">
-        <div class="page-header"><h1>HTTP Response</h1></div>
-        {httpResponse}
+      <section id="http-request">
+        <div class="page-header"><h1>HTTP Request</h1></div>
+        {httpRequest(request)}
       </section>
+      {response match {
+        case None =>
+        case Some(some) =>
+          <section id="http-response">
+            <div class="page-header"><h1>HTTP Response</h1></div>
+            {httpResponse(some)}
+          </section>
+      }}
     </xml:group>
 
     def sidebar = <div id="navbar" class="sidebar-nav sidebar-nav-fixed">
       <ul class="nav nav-list">
-        {result match {
-        case Left(_) =>
+        {collection match {
+        case None =>
+        case Some(Left(_)) =>
           <li class="nav-header"><a href="#server-error">Server Error</a></li>
-        case Right(cj) =>
+        case Some(Right(cj)) =>
           {try {
             <xml:group>
               <li class="nav-header active"><a href="#meta">Meta</a></li>
               {cj.links.zipWithIndex map { case (l, i) =>
-                <li><a href={"#link-" + (i + 1)}>{getName(l, "Link", i + 1)}</a></li>
+                <li><a href={"#link-" + (i + 1)}>{getName(l, "Link ", i + 1)}</a></li>
               }}
               {if(cj.items.nonEmpty) {
                 <xml:group>
@@ -532,10 +584,26 @@ class Views(baseUrl: String) {
               {cj.template map { _ => <li class="nav-header"><a href="#template">Template</a></li> } getOrElse NodeSeq.Empty }
               {cj.error map { _ => <li class="nav-header"><a href="#error">Error</a></li> } getOrElse NodeSeq.Empty }
               <li class="nav-header"><a href="#formatted-body">Formatted Body</a></li>
-              <li class="nav-header"><a href="#http-response">HTTP Response</a></li>
             </xml:group>
           } catch { case ex: Exception => <div>Unable to process model: {ex.getMessage}</div> }}
         }}
+        <li class="nav-header"><a href="#http-request">HTTP Request</a></li>
+        {
+        response match {
+          case None =>
+          case Some(some) =>
+            <li class="nav-header"><a href="#http-response">HTTP Response</a></li>
+            /*
+            <xml:group>
+              <li class="nav-header"><a href="#http-response">HTTP Response</a></li>
+              {some match {
+                case Right(_) =>
+                  <li class="nav-header"><a href="#formatted-body">Formatted Body</a></li>
+                case _ =>
+              }}
+            </xml:group>
+            */
+        }}
       </ul>
     </div>