Code formatting and cleanup (#442)

* Formatting, extract error messages
* More refactor
* Move errors to a separate file
* Add missing file
* Misc

pkg/api/api.go

@@ -2,7 +2,6 @@ package api
 
 import (
 	"encoding/base64"
-	"errors"
 	"fmt"
 	neturl "net/url"
 	"regexp"
@@ -31,11 +30,11 @@ var (
 func DB(c *gin.Context) *client.Client {
 	if command.Opts.Sessions {
 		return DbSessions[getSessionId(c.Request)]
-	} else {
-		return DbClient
 	}
+	return DbClient
 }
 
+// setClient sets the database client connection for the sessions
 func setClient(c *gin.Context, newClient *client.Client) error {
 	currentClient := DB(c)
 	if currentClient != nil {
@@ -47,23 +46,26 @@ func setClient(c *gin.Context, newClient *client.Client) error {
 		return nil
 	}
 
-	sessionId := getSessionId(c.Request)
-	if sessionId == "" {
-		return errors.New("Session ID is required")
+	sid := getSessionId(c.Request)
+	if sid == "" {
+		return errSessionRequired
 	}
 
-	DbSessions[sessionId] = newClient
+	DbSessions[sid] = newClient
 	return nil
 }
 
+// GetHome renderes the home page
 func GetHome(c *gin.Context) {
 	serveStaticAsset("/index.html", c)
 }
 
+// GetAsset renders the requested static asset
 func GetAsset(c *gin.Context) {
 	serveStaticAsset(c.Params.ByName("path"), c)
 }
 
+// GetSessions renders the number of active sessions
 func GetSessions(c *gin.Context) {
 	// In debug mode endpoint will return a lot of sensitive information
 	// like full database connection string and all query history.
@@ -74,6 +76,7 @@ func GetSessions(c *gin.Context) {
 	successResponse(c, gin.H{"sessions": len(DbSessions)})
 }
 
+// ConnectWithBackend creates a new connection based on backend resource
 func ConnectWithBackend(c *gin.Context) {
 	// Setup a new backend client
 	backend := Backend{
@@ -90,12 +93,12 @@ func ConnectWithBackend(c *gin.Context) {
 	}
 
 	// Make the new session
-	sessionId, err := securerandom.Uuid()
+	sid, err := securerandom.Uuid()
 	if err != nil {
 		badRequest(c, err)
 		return
 	}
-	c.Request.Header.Add("x-session-id", sessionId)
+	c.Request.Header.Add("x-session-id", sid)
 
 	// Connect to the database
 	cl, err := client.NewFromUrl(cred.DatabaseURL, nil)
@@ -116,20 +119,22 @@ func ConnectWithBackend(c *gin.Context) {
 		return
 	}
 
-	c.Redirect(301, fmt.Sprintf("/%s?session=%s", command.Opts.Prefix, sessionId))
+	redirectURI := fmt.Sprintf("/%s?session=%s", command.Opts.Prefix, sid)
+	c.Redirect(301, redirectURI)
 }
 
+// Connect creates a new client connection
 func Connect(c *gin.Context) {
 	if command.Opts.LockSession {
-		badRequest(c, "Session is locked")
+		badRequest(c, errSessionLocked)
 		return
 	}
 
 	var sshInfo *shared.SSHInfo
 	url := c.Request.FormValue("url")
 
 	if url == "" {
-		badRequest(c, "Url parameter is required")
+		badRequest(c, errURLRequired)
 		return
 	}
 
@@ -170,9 +175,10 @@ func Connect(c *gin.Context) {
 	successResponse(c, info.Format()[0])
 }
 
+// SwitchDb perform database switch for the client connection
 func SwitchDb(c *gin.Context) {
 	if command.Opts.LockSession {
-		badRequest(c, "Session is locked")
+		badRequest(c, errSessionLocked)
 		return
 	}
 
@@ -181,31 +187,30 @@ func SwitchDb(c *gin.Context) {
 		name = c.Request.FormValue("db")
 	}
 	if name == "" {
-		badRequest(c, "Database name is not provided")
+		badRequest(c, errDatabaseNameRequired)
 		return
 	}
 
 	conn := DB(c)
 	if conn == nil {
-		badRequest(c, "Not connected")
+		badRequest(c, errNotConnected)
 		return
 	}
 
 	// Do not allow switching databases for connections from third-party backends
 	if conn.External {
-		badRequest(c, "Session is locked")
+		badRequest(c, errSessionLocked)
 		return
 	}
 
-	currentUrl, err := neturl.Parse(conn.ConnectionString)
+	currentURL, err := neturl.Parse(conn.ConnectionString)
 	if err != nil {
-		badRequest(c, "Unable to parse current connection string")
+		badRequest(c, errInvalidConnString)
 		return
 	}
+	currentURL.Path = name
 
-	currentUrl.Path = name
-
-	cl, err := client.NewFromUrl(currentUrl.String(), nil)
+	cl, err := client.NewFromUrl(currentURL.String(), nil)
 	if err != nil {
 		badRequest(c, err)
 		return
@@ -232,16 +237,16 @@ func SwitchDb(c *gin.Context) {
 	successResponse(c, info.Format()[0])
 }
 
+// Disconnect closes the current database connection
 func Disconnect(c *gin.Context) {
 	if command.Opts.LockSession {
-		badRequest(c, "Session is locked")
+		badRequest(c, errSessionLocked)
 		return
 	}
 
 	conn := DB(c)
-
 	if conn == nil {
-		badRequest(c, "Not connected")
+		badRequest(c, errNotConnected)
 		return
 	}
 
@@ -254,53 +259,59 @@ func Disconnect(c *gin.Context) {
 	successResponse(c, gin.H{"success": true})
 }
 
-func GetDatabases(c *gin.Context) {
-	conn := DB(c)
-	if conn.External {
-		errorResponse(c, 403, "Not permitted")
-		return
-	}
-
-	names, err := DB(c).Databases()
-	serveResult(c, names, err)
-}
-
-func GetObjects(c *gin.Context) {
-	result, err := DB(c).Objects()
-	if err != nil {
-		badRequest(c, err)
-		return
-	}
-	successResponse(c, client.ObjectsFromResult(result))
-}
-
+// RunQuery executes the query
 func RunQuery(c *gin.Context) {
 	query := cleanQuery(c.Request.FormValue("query"))
 
 	if query == "" {
-		badRequest(c, "Query parameter is missing")
+		badRequest(c, errQueryRequired)
 		return
 	}
 
 	HandleQuery(query, c)
 }
 
+// ExplainQuery renders query analyze profile
 func ExplainQuery(c *gin.Context) {
 	query := cleanQuery(c.Request.FormValue("query"))
 
 	if query == "" {
-		badRequest(c, "Query parameter is missing")
+		badRequest(c, errQueryRequired)
 		return
 	}
 
 	HandleQuery(fmt.Sprintf("EXPLAIN ANALYZE %s", query), c)
 }
 
+// GetDatabases renders a list of all databases on the server
+func GetDatabases(c *gin.Context) {
+	conn := DB(c)
+	if conn.External {
+		errorResponse(c, 403, errNotPermitted)
+		return
+	}
+
+	names, err := DB(c).Databases()
+	serveResult(c, names, err)
+}
+
+// GetObjects renders a list of database objects
+func GetObjects(c *gin.Context) {
+	result, err := DB(c).Objects()
+	if err != nil {
+		badRequest(c, err)
+		return
+	}
+	successResponse(c, client.ObjectsFromResult(result))
+}
+
+// GetSchemas renders list of available schemas
 func GetSchemas(c *gin.Context) {
 	res, err := DB(c).Schemas()
 	serveResult(c, res, err)
 }
 
+// GetTable renders table information
 func GetTable(c *gin.Context) {
 	var res *client.Result
 	var err error
@@ -314,6 +325,7 @@ func GetTable(c *gin.Context) {
 	serveResult(c, res, err)
 }
 
+// GetTableRows renders table rows
 func GetTableRows(c *gin.Context) {
 	offset, err := parseIntFormValue(c, "offset", 0)
 	if err != nil {
@@ -366,6 +378,7 @@ func GetTableRows(c *gin.Context) {
 	serveResult(c, res, err)
 }
 
+// GetTableInfo renders a selected table information
 func GetTableInfo(c *gin.Context) {
 	res, err := DB(c).TableInfo(c.Params.ByName("table"))
 	if err == nil {
@@ -375,10 +388,12 @@ func GetTableInfo(c *gin.Context) {
 	}
 }
 
+// GetHistory renders a list of recent queries
 func GetHistory(c *gin.Context) {
 	successResponse(c, DB(c).History)
 }
 
+// GetConnectionInfo renders information about current connection
 func GetConnectionInfo(c *gin.Context) {
 	res, err := DB(c).Info()
 
@@ -393,21 +408,25 @@ func GetConnectionInfo(c *gin.Context) {
 	successResponse(c, info)
 }
 
+// GetActivity renders a list of running queries
 func GetActivity(c *gin.Context) {
 	res, err := DB(c).Activity()
 	serveResult(c, res, err)
 }
 
+// GetTableIndexes renders a list of database table indexes
 func GetTableIndexes(c *gin.Context) {
 	res, err := DB(c).TableIndexes(c.Params.ByName("table"))
 	serveResult(c, res, err)
 }
 
+// GetTableConstraints renders a list of database constraints
 func GetTableConstraints(c *gin.Context) {
 	res, err := DB(c).TableConstraints(c.Params.ByName("table"))
 	serveResult(c, res, err)
 }
 
+// HandleQuery runs the database query
 func HandleQuery(query string, c *gin.Context) {
 	rawQuery, err := base64.StdEncoding.DecodeString(desanitize64(query))
 	if err == nil {
@@ -443,11 +462,13 @@ func HandleQuery(query string, c *gin.Context) {
 	}
 }
 
+// GetBookmarks renders the list of available bookmarks
 func GetBookmarks(c *gin.Context) {
 	bookmarks, err := bookmarks.ReadAll(bookmarks.Path(command.Opts.BookmarksDir))
 	serveResult(c, bookmarks, err)
 }
 
+// GetInfo renders the pgweb system information
 func GetInfo(c *gin.Context) {
 	successResponse(c, gin.H{
 		"version":    command.Version,
@@ -456,7 +477,7 @@ func GetInfo(c *gin.Context) {
 	})
 }
 
-// Export database or table data
+// DataExport performs database table export
 func DataExport(c *gin.Context) {
 	db := DB(c)
 
@@ -473,7 +494,7 @@ func DataExport(c *gin.Context) {
 	// If pg_dump is not available the following code will not show an error in browser.
 	// This is due to the headers being written first.
 	if !dump.CanExport() {
-		badRequest(c, "pg_dump is not found")
+		badRequest(c, errPgDumpNotFound)
 		return
 	}
 

pkg/api/backend.go

@@ -54,7 +54,7 @@ func (be Backend) FetchCredential(resource string, c *gin.Context) (*BackendCred
 		log.Println("Unable to fetch backend credential:", err)
 
 		// We dont want to expose the url of the backend here, so reply with generic error
-		return nil, fmt.Errorf("Unable to connect to the auth backend")
+		return nil, errBackendConnectError
 	}
 	defer resp.Body.Close()
 
@@ -67,7 +67,7 @@ func (be Backend) FetchCredential(resource string, c *gin.Context) (*BackendCred
 		return nil, err
 	}
 	if cred.DatabaseURL == "" {
-		return nil, fmt.Errorf("Database URL was not provided")
+		return nil, errConnStringRequired
 	}
 
 	return cred, nil

pkg/api/errors.go

@@ -0,0 +1,19 @@
+package api
+
+import (
+	"errors"
+)
+
+var (
+	errNotConnected         = errors.New("Not connected")
+	errNotPermitted         = errors.New("Not permitted")
+	errConnStringRequired   = errors.New("Connection string is required")
+	errInvalidConnString    = errors.New("Invalid connection string")
+	errSessionRequired      = errors.New("Session ID is required")
+	errSessionLocked        = errors.New("Session is locked")
+	errURLRequired          = errors.New("URL parameter is required")
+	errQueryRequired        = errors.New("Query parameter is required")
+	errDatabaseNameRequired = errors.New("Database name is required")
+	errPgDumpNotFound       = errors.New("pg_dump utility is not found")
+	errBackendConnectError  = errors.New("Unable to connect to the auth backend")
+)