Remove errors.go

This commit refactors the codebase. The functionality of the error
handling is slightly reduced but the benefit are around 80 lines of code
which could be removed.

3 files changed, 18 insertions, 102 deletions

diff --git a/errors.go b/errors.go
deleted file mode 100644
index 193cc11..0000000
--- a/errors.go
+++ /dev/null
@@ -1,84 +0,0 @@
-
-package main
-
-import (
-	"fmt"
-	"log"
-	"net/http"
-)
-
-func Err(w http.ResponseWriter, code int, a ...interface{}) {
-
-	var msg string  // format string for error message
-	var hc int      // HTTP error code
-
-	var prefix string = fmt.Sprintf("Error %d - ", code)
-
-	// ATTENTION: the used error codes in this switch statements should be
-	// stable. Do not change them, just append to the list!
-	switch code {
-
-		case 1:
-			msg = "Failed to load recipes from database."
-			hc = http.StatusInternalServerError
-
-		case 2:
-			msg = "Could not parse recipe from database request."
-			hc = http.StatusInternalServerError
-
-		case 3:
-			msg = "Exactly 1 'id' URL parameter expected but %d provided."
-			hc = http.StatusBadRequest
-
-		case 4:
-			msg = "'id' URL parameter '%s' doas not match the regex '%s'."
-			hc = http.StatusBadRequest
-
-		case 5:
-			msg = "Received error from database: '%s'."
-			hc = http.StatusInternalServerError
-
-		case 6:
-			msg = "Expected exactly 1 recipe from database but got %d."
-			hc = http.StatusInternalServerError
-
-		// deprecated
-		case 7:
-			msg = "Exactly 1 'type' URL parameter expected but %d provided."
-			hc = http.StatusBadRequest
-
-		case 8:
-			msg = "Form data does not contain recipe URL (key is '%s')."
-			hc = http.StatusBadRequest
-
-		case 9:
-			msg = "Could not add recipe: '%s'."
-			hc = http.StatusInternalServerError
-
-		case 10:
-			msg = "Expected exactly 1 recipe URL in '%s' but got %d (regex is '%s')."
-			hc = http.StatusBadRequest
-
-		case 11:
-			msg = "Could not get recipe ID from database: '%s'."
-			hc = http.StatusInternalServerError
-
-		// deprecated
-		case 12:
-			msg = "Given recipe type '%s' is unknown."
-			hc = http.StatusBadRequest
-
-		default:
-			msg = "An unknown error occured."
-			hc = http.StatusInternalServerError
-
-	}
-
-	// format full error message
-	final := fmt.Sprintf(prefix + msg, a...)
-
-	// send message to log and user
-	log.Println(final)
-	http.Error(w, final, hc)
-
-}
diff --git a/handler.go b/handler.go
index 1c922fe..fc3d653 100644
--- a/handler.go
+++ b/handler.go
@@ -33,7 +33,7 @@ func indexGet(w http.ResponseWriter, r *http.Request, db *Database, templateRoot
 	log.Printf("Query: %s", cmd)
 	rows, err := db.Backend.Query(cmd)
 	if err != nil {
-		Err(w, 1)
+		http.Error(w, "Failed to load recipes from database.", 500)
 		return
 	}
 	defer rows.Close()
@@ -50,7 +50,7 @@ func indexGet(w http.ResponseWriter, r *http.Request, db *Database, templateRoot
 		var element Element
 		err := rows.Scan(&element.Id, &element.Title)
 		if err != nil {
-			Err(w, 2)
+			http.Error(w, "Could not parse recipe from database request.", 500)
 			return
 		} else {
 			elements = append(elements, element)
@@ -69,7 +69,8 @@ func recipe(db *Database, templateRoot string) func(http.ResponseWriter, *http.R
 		// get id from URL parameters
 		ids := r.URL.Query()["id"]
 		if len(ids) != 1 {
-			Err(w, 3, len(ids))
+			msg := fmt.Sprintf("Exactly 1 'id' URL parameter expected but %d provided.", len(ids))
+			http.Error(w, msg, 400)
 			return
 		}
 		idStr := ids[0]
@@ -77,7 +78,7 @@ func recipe(db *Database, templateRoot string) func(http.ResponseWriter, *http.R
 		// validate id
 		idRegex := regexp.MustCompile(VALID_ID_REGEX)
 		if !(idRegex.MatchString(idStr)) {
-			Err(w, 4, idStr, VALID_ID_REGEX)
+			http.Error(w, "Bad 'id' URL parameter.", 400)
 			return
 		}
 
@@ -88,7 +89,7 @@ func recipe(db *Database, templateRoot string) func(http.ResponseWriter, *http.R
 			log.Printf("Query: %s", cmd)
 			rows, err := db.Backend.Query(cmd)
 			if err != nil {
-				Err(w, 5, err)
+				http.Error(w, "Database returned error: " + err.Error(), 500)
 				return
 			}
 			defer rows.Close()
@@ -109,7 +110,7 @@ func recipe(db *Database, templateRoot string) func(http.ResponseWriter, *http.R
 				element.Id = idStr
 				err := rows.Scan(&element.Title, &element.UpstreamUrl, &element.DescriptionMarkdown)
 				if err != nil {
-					Err(w, 2)
+					http.Error(w, "Could not parse recipe from database request.", 500)
 					return
 				} else {
 					elements = append(elements, element)
@@ -118,7 +119,7 @@ func recipe(db *Database, templateRoot string) func(http.ResponseWriter, *http.R
 
 			// check result
 			if len(elements) != 1 {
-				Err(w, 6, len(elements))
+				http.Error(w, "Expected exactly 1 recipe from database.", 500)
 				return
 			}
 
@@ -150,7 +151,7 @@ func recipe_edit(db *Database, templateRoot string) func(http.ResponseWriter, *h
 		// get id from URL parameters
 		ids := r.URL.Query()["id"]
 		if len(ids) != 1 {
-			Err(w, 3, len(ids))
+			http.Error(w, "Exactly 1 'id' URL parameter expected.", 400)
 			return
 		}
 		idStr := ids[0]
@@ -158,7 +159,7 @@ func recipe_edit(db *Database, templateRoot string) func(http.ResponseWriter, *h
 		// validate id
 		idRegex := regexp.MustCompile(VALID_ID_REGEX)
 		if !(idRegex.MatchString(idStr)) {
-			Err(w, 4, idStr, VALID_ID_REGEX)
+			http.Error(w, "Bad 'id' URL parameter.", 400)
 			return
 		}
 
@@ -169,7 +170,7 @@ func recipe_edit(db *Database, templateRoot string) func(http.ResponseWriter, *h
 			log.Printf("Query: %s", cmd)
 			rows, err := db.Backend.Query(cmd)
 			if err != nil {
-				Err(w, 5, err)
+				http.Error(w, "Got error from database: " + err.Error(), 500)
 				return
 			}
 			defer rows.Close()
@@ -190,7 +191,7 @@ func recipe_edit(db *Database, templateRoot string) func(http.ResponseWriter, *h
 				element.Id = idStr
 				err := rows.Scan(&element.Title, &element.UpstreamUrl, &element.DescriptionMarkdown)
 				if err != nil {
-					Err(w, 2)
+					http.Error(w, "Could not parse recipe from database request.", 500)
 					return
 				} else {
 					elements = append(elements, element)
@@ -199,7 +200,7 @@ func recipe_edit(db *Database, templateRoot string) func(http.ResponseWriter, *h
 
 			// check result
 			if len(elements) != 1 {
-				Err(w, 6, len(elements))
+				http.Error(w, "Did not get exactly one recipe from database.", 500)
 				return
 			}
 
@@ -248,7 +249,7 @@ func image(storageRoot string) func(http.ResponseWriter, *http.Request) {
 		// get ID
 		ids := r.URL.Query()["id"]
 		if len(ids) != 1 {
-			Err(w, 3, len(ids))
+			http.Error(w, "Expected exactly one 'id' URL parameter.", 400)
 			return
 		}
 		idStr := ids[0]
@@ -256,7 +257,7 @@ func image(storageRoot string) func(http.ResponseWriter, *http.Request) {
 		// validate ID
 		idRegex := regexp.MustCompile(VALID_ID_REGEX)
 		if !idRegex.MatchString(idStr) {
-			Err(w, 4, idStr, VALID_ID_REGEX)
+			http.Error(w, "Bad 'id' URL parameter.", 400)
 			return
 		}
 
@@ -286,12 +287,12 @@ func add_recipes(db *Database, storageRoot string, staticRoot string) func(http.
 			log.Println(cmd)
 			res,err := db.Backend.Exec(cmd)
 			if err != nil {
-				Err(w, 9, err)
+				http.Error(w, "Could not add recipe.", 500)
 				return
 			}
 			id,err := res.LastInsertId()
 			if err != nil {
-				Err(w, 11, err)
+				http.Error(w, "Expected exactly one recipe URL.", 400)
 				return
 			} else {
 				log.Println("Added custom recipe.")
diff --git a/router.go b/router.go
index a75988b..508d23d 100644
--- a/router.go
+++ b/router.go
@@ -7,13 +7,12 @@ import (
 )
 
 func indexMux(db *Database, templateRoot string) func(http.ResponseWriter, *http.Request) {
-
 	return func(w http.ResponseWriter, r *http.Request) {
 		switch r.Method {
 		case "GET":
 			indexGet(w, r, db, templateRoot)
 		default:
-			// TODO
+			http.Error(w, "Bad Request", 400)
 		}
 	}
 }