Make pgweb to use multiple sessions at once [wip]

pkg/api/api.go

@@ -15,6 +15,11 @@ import (
 )
 
 var DbClient *client.Client
+var DbSessions = map[string]*client.Client{}
+
+func DB(c *gin.Context) *client.Client {
+	return DbSessions[getSessionId(c)]
+}
 
 func GetHome(c *gin.Context) {
 	serveStaticAsset("/index.html", c)
@@ -24,6 +29,10 @@ func GetAsset(c *gin.Context) {
 	serveStaticAsset(c.Params.ByName("path"), c)
 }
 
+func GetSessions(c *gin.Context) {
+	c.JSON(200, DbSessions)
+}
+
 func Connect(c *gin.Context) {
 	url := c.Request.FormValue("url")
 
@@ -32,6 +41,12 @@ func Connect(c *gin.Context) {
 		return
 	}
 
+	sessionId := getSessionId(c)
+	if sessionId == "" {
+		c.JSON(400, Error{"Session ID is required"})
+		return
+	}
+
 	opts := command.Options{Url: url}
 	url, err := connection.FormatUrl(opts)
 
@@ -55,18 +70,19 @@ func Connect(c *gin.Context) {
 	info, err := cl.Info()
 
 	if err == nil {
-		if DbClient != nil {
-			DbClient.Close()
+		db := DbSessions[sessionId]
+		if db != nil {
+			db.Close()
 		}
 
-		DbClient = cl
+		DbSessions[sessionId] = cl
 	}
 
 	c.JSON(200, info.Format()[0])
 }
 
 func GetDatabases(c *gin.Context) {
-	names, err := DbClient.Databases()
+	names, err := DB(c).Databases()
 	serveResult(names, err, c)
 }
 
@@ -93,17 +109,17 @@ func ExplainQuery(c *gin.Context) {
 }
 
 func GetSchemas(c *gin.Context) {
-	names, err := DbClient.Schemas()
+	names, err := DB(c).Schemas()
 	serveResult(names, err, c)
 }
 
 func GetTables(c *gin.Context) {
-	names, err := DbClient.Tables()
+	names, err := DB(c).Tables()
 	serveResult(names, err, c)
 }
 
 func GetTable(c *gin.Context) {
-	res, err := DbClient.Table(c.Params.ByName("table"))
+	res, err := DB(c).Table(c.Params.ByName("table"))
 	serveResult(res, err, c)
 }
 
@@ -128,13 +144,13 @@ func GetTableRows(c *gin.Context) {
 		Where:      c.Request.FormValue("where"),
 	}
 
-	res, err := DbClient.TableRows(c.Params.ByName("table"), opts)
+	res, err := DB(c).TableRows(c.Params.ByName("table"), opts)
 	if err != nil {
 		c.JSON(400, NewError(err))
 		return
 	}
 
-	countRes, err := DbClient.TableRowsCount(c.Params.ByName("table"), opts)
+	countRes, err := DB(c).TableRowsCount(c.Params.ByName("table"), opts)
 	if err != nil {
 		c.JSON(400, NewError(err))
 		return
@@ -160,7 +176,7 @@ func GetTableRows(c *gin.Context) {
 }
 
 func GetTableInfo(c *gin.Context) {
-	res, err := DbClient.TableInfo(c.Params.ByName("table"))
+	res, err := DB(c).TableInfo(c.Params.ByName("table"))
 
 	if err != nil {
 		c.JSON(400, NewError(err))
@@ -171,11 +187,11 @@ func GetTableInfo(c *gin.Context) {
 }
 
 func GetHistory(c *gin.Context) {
-	c.JSON(200, DbClient.History)
+	c.JSON(200, DB(c).History)
 }
 
 func GetConnectionInfo(c *gin.Context) {
-	res, err := DbClient.Info()
+	res, err := DB(c).Info()
 
 	if err != nil {
 		c.JSON(400, NewError(err))
@@ -186,22 +202,22 @@ func GetConnectionInfo(c *gin.Context) {
 }
 
 func GetSequences(c *gin.Context) {
-	res, err := DbClient.Sequences()
+	res, err := DB(c).Sequences()
 	serveResult(res, err, c)
 }
 
 func GetActivity(c *gin.Context) {
-	res, err := DbClient.Activity()
+	res, err := DB(c).Activity()
 	serveResult(res, err, c)
 }
 
 func GetTableIndexes(c *gin.Context) {
-	res, err := DbClient.TableIndexes(c.Params.ByName("table"))
+	res, err := DB(c).TableIndexes(c.Params.ByName("table"))
 	serveResult(res, err, c)
 }
 
 func GetTableConstraints(c *gin.Context) {
-	res, err := DbClient.TableConstraints(c.Params.ByName("table"))
+	res, err := DB(c).TableConstraints(c.Params.ByName("table"))
 	serveResult(res, err, c)
 }
 
@@ -211,7 +227,7 @@ func HandleQuery(query string, c *gin.Context) {
 		query = string(rawQuery)
 	}
 
-	result, err := DbClient.Query(query)
+	result, err := DB(c).Query(query)
 	if err != nil {
 		c.JSON(400, NewError(err))
 		return

pkg/api/helpers.go

@@ -20,10 +20,27 @@ var extraMimeTypes = map[string]string{
 	".html": "text/html; charset-utf-8",
 }
 
+// Paths that dont require database connection
+var allowedPaths = map[string]bool{
+	"/api/sessions":  true,
+	"/api/info":      true,
+	"/api/connect":   true,
+	"/api/bookmarks": true,
+	"/api/history":   true,
+}
+
 type Error struct {
 	Message string `json:"error"`
 }
 
+func getSessionId(c *gin.Context) string {
+	id := c.Request.Header.Get("x-session-id")
+	if id == "" {
+		id = c.Request.URL.Query().Get("_session_id")
+	}
+	return id
+}
+
 func getQueryParam(c *gin.Context, name string) string {
 	result := ""
 	q := c.Request.URL.Query()
@@ -75,37 +92,28 @@ func NewError(err error) Error {
 
 // Middleware function to check database connection status before running queries
 func dbCheckMiddleware() gin.HandlerFunc {
-	allowedPaths := []string{
-		"/api/info",
-		"/api/connect",
-		"/api/bookmarks",
-		"/api/history",
-	}
-
 	return func(c *gin.Context) {
-		if DbClient != nil {
+		if allowedPaths[c.Request.URL.Path] == true {
 			c.Next()
 			return
 		}
 
-		currentPath := c.Request.URL.Path
-		allowed := false
-
-		for _, path := range allowedPaths {
-			if path == currentPath {
-				allowed = true
-				break
-			}
+		sessionId := getSessionId(c)
+		if sessionId == "" {
+			c.JSON(400, Error{"Session ID is required"})
+			c.Abort()
+			return
 		}
 
-		if allowed {
-			c.Next()
-		} else {
+		conn := DbSessions[sessionId]
+		if conn == nil {
 			c.JSON(400, Error{"Not connected"})
 			c.Abort()
+			return
 		}
 
-		return
+		c.Set("db", conn)
+		c.Next()
 	}
 }
 
@@ -113,7 +121,6 @@ func dbCheckMiddleware() gin.HandlerFunc {
 func requestInspectMiddleware() gin.HandlerFunc {
 	return func(c *gin.Context) {
 		err := c.Request.ParseForm()
-
 		log.Println("Request params:", err, c.Request.Form)
 	}
 }

pkg/api/routes.go

@@ -22,6 +22,7 @@ func SetupRoutes(router *gin.Engine) {
 		SetupMiddlewares(api)
 
 		api.GET("/info", GetInfo)
+		api.GET("/sessions", GetSessions)
 		api.POST("/connect", Connect)
 		api.GET("/databases", GetDatabases)
 		api.GET("/connection", GetConnectionInfo)

static/js/app.js

@@ -16,6 +16,22 @@ var filterOptions = {
   "not_null":   "IS NOT NULL"
 };
 
+function guid() {
+  function s4() { return Math.floor((1 + Math.random()) * 0x10000).toString(16).substring(1); }
+  return [s4(), s4(), "-", s4(), "-", s4(), "-", s4(), "-", s4(), s4(), s4()].join("");
+}
+
+function getSessionId() {
+  var id = localStorage.getItem("session_id");
+
+  if (!id) {
+    id = guid();
+    localStorage.setItem("session_id", id);
+  }
+
+  return id;
+}
+
 function setRowsLimit(num) {
   localStorage.setItem("rows_limit", num);
 }
@@ -47,6 +63,9 @@ function apiCall(method, path, params, cb) {
     method: method,
     cache: false,
     data: params,
+    headers: {
+      "x-session-id": getSessionId()
+    },
     success: function(data) {
       cb(data);
     },