Issue #28: Add error field in API error responses

Signed-off-by: Lucas Fernandes de Oliveira <lfo14@inf.ufpr.br>

src/api/controllers/data.spec.ts

@@ -52,9 +52,12 @@ describe("API data controller", () => {
             .expect((res: any) => {
                 const message = "Query execution failed: " +
                 "Could not construct query with the paramters given.";
+                const error = "The metric named met:-1 was not found";
                 expect(res.body).to.be.an("object");
                 expect(res.body).to.have.property("message");
+                expect(res.body).to.have.property("error");
                 expect(res.body.message).to.be.eql(message);
+                expect(res.body.error).to.be.eql(error);
             })
             .end(done);
     });
@@ -67,9 +70,12 @@ describe("API data controller", () => {
             .expect((res: any) => {
                 const message = "Query execution failed: " +
                 "Could not construct query with the paramters given.";
+                const error = "The dimension named dim:11 was not found";
                 expect(res.body).to.be.an("object");
                 expect(res.body).to.have.property("message");
+                expect(res.body).to.have.property("error");
                 expect(res.body.message).to.be.eql(message);
+                expect(res.body.error).to.be.eql(error);
             })
             .end(done);
     });

src/api/controllers/data.ts

@@ -48,15 +48,21 @@ export class DataCtrl {
             view = req.engine.query(query);
         }
         catch (e) {
-            res.status(500).json({ message: "Query execution failed: " +
-                "Could not construct query with the paramters given." });
+            res.status(500).json({
+                message: "Query execution failed: " +
+                "Could not construct query with the paramters given.",
+                error: e.message
+             });
             return;
         }
 
         req.adapter.getDataFromView(view, (err: Error, result: any[]) => {
             if (err) {
-                res.status(500).json({ message: "Query execution failed " +
-                    "failed on execute query on database." });
+                res.status(500).json({
+                    message: "Query execution failed " +
+                    "failed on execute query on database.",
+                    error: err
+                 });
                 return;
             }