Store username in array from login to server

0

I have a small Go web-server that displays data to users as they login. The problem I'm trying to achieve is to have the web-page only show certain information when a specific user logs in. For example, when admin logs in there would be a list of admin-only items that they can see on the web-page.

The problem I'm having is for some reason my Go code isn't storing the username in the array that I'm calling, so when I pass it over to the JavaScript it is blank.

Here are the 3 main parts of the code that I'm struggling with:

main.go

package main



import "fmt"



func authHandler(w http.ResponseWriter, r *http.Request) {

    r.ParseForm()

    usernameArray, hasUsername := r.PostForm["j_username"]



    //This line added for debugging purposes

    log.Println("username:", usernameArray[0])



    if hasUsername {

        fmt.Fprintf(w, "%s", usernameArray[0])

    }

}



func main() {

    http.HandleFunc("/getAuth", authHandler)

}

---

javascript.js

Note that this is AngularJS

$scope.init = function() {

    checkAuthentication();

};



checkAuthentication = function() {

    $http.get("/getAuth").then(

    function(response) {

        var username = response.data;



        console.log(username): //Added for debugging purposes



        if (username === "admin") {

            $scope.showAdminOnlyItems = true;

        }

    });

}

---

main.html

<div id="admin-only-items" ng-show="showAdminOnlyItems">

    <hr style="border:1px solid">

    <p style="text-align: center">admin only: </p>

    <div id="adminOnlyButtom">

        <button class="button" data-ng-click="doSomething()">Do something</button>

    </div>

</div>

Again, I only want that div to show up when admin logs in, and Go needs to send the username over to the javascript to verify that. By adding the debugging line in Go and starting the server up, I get this:

2018/11/19 16:28:42 http: panic serving 10.240.49.238:59621: runtime error: 

index out of range

goroutine 26 [running]:

net/http.(*conn).serve.func1(0xc42009f720)

        C:/Go/src/net/http/server.go:1726 +0xd0

panic(0x79f820, 0xe17940)

        C:/Go/src/runtime/panic.go:502 +0x229

main.authHandler(0xc56220, 0xc420135180, 0xc4207a3500)

        D:/src/main.go:346 +0x1d8

So it's clear that the usernameArray is empty, not sure what I did wrong. Can anyone help tell me why the usernameArray is empty in authHandler?

javascript html arrays angularjs go

share|improve this question

edited Nov 20 '18 at 7:51

Flimzy

37.7k96497

asked Nov 19 '18 at 23:56

WitchKing17WitchKing17

8310

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  You should check for error value returned from r.ParseForm() and use r.PostFormValue() instead.
  
  – Pie 'Oh' Pah
  Nov 20 '18 at 0:30
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  Also note that r.PostFormValue() would be for a PUT, PATCH, or POST. You're sending an http GET method, which is not expended to send any data.
  
  – Slotheroo
  Nov 20 '18 at 0:32
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  How are you sending request data to Go in the first place? The javascript code only send GET request with no data.
  
  – Pie 'Oh' Pah
  Nov 20 '18 at 1:02
  

  
  
  
  

add a comment | 

0

I have a small Go web-server that displays data to users as they login. The problem I'm trying to achieve is to have the web-page only show certain information when a specific user logs in. For example, when admin logs in there would be a list of admin-only items that they can see on the web-page.

The problem I'm having is for some reason my Go code isn't storing the username in the array that I'm calling, so when I pass it over to the JavaScript it is blank.

Here are the 3 main parts of the code that I'm struggling with:

main.go

package main



import "fmt"



func authHandler(w http.ResponseWriter, r *http.Request) {

    r.ParseForm()

    usernameArray, hasUsername := r.PostForm["j_username"]



    //This line added for debugging purposes

    log.Println("username:", usernameArray[0])



    if hasUsername {

        fmt.Fprintf(w, "%s", usernameArray[0])

    }

}



func main() {

    http.HandleFunc("/getAuth", authHandler)

}

---

javascript.js

Note that this is AngularJS

$scope.init = function() {

    checkAuthentication();

};



checkAuthentication = function() {

    $http.get("/getAuth").then(

    function(response) {

        var username = response.data;



        console.log(username): //Added for debugging purposes



        if (username === "admin") {

            $scope.showAdminOnlyItems = true;

        }

    });

}

---

main.html

<div id="admin-only-items" ng-show="showAdminOnlyItems">

    <hr style="border:1px solid">

    <p style="text-align: center">admin only: </p>

    <div id="adminOnlyButtom">

        <button class="button" data-ng-click="doSomething()">Do something</button>

    </div>

</div>

Again, I only want that div to show up when admin logs in, and Go needs to send the username over to the javascript to verify that. By adding the debugging line in Go and starting the server up, I get this:

2018/11/19 16:28:42 http: panic serving 10.240.49.238:59621: runtime error: 

index out of range

goroutine 26 [running]:

net/http.(*conn).serve.func1(0xc42009f720)

        C:/Go/src/net/http/server.go:1726 +0xd0

panic(0x79f820, 0xe17940)

        C:/Go/src/runtime/panic.go:502 +0x229

main.authHandler(0xc56220, 0xc420135180, 0xc4207a3500)

        D:/src/main.go:346 +0x1d8

So it's clear that the usernameArray is empty, not sure what I did wrong. Can anyone help tell me why the usernameArray is empty in authHandler?

javascript html arrays angularjs go

share|improve this question

edited Nov 20 '18 at 7:51

Flimzy

37.7k96497

asked Nov 19 '18 at 23:56

WitchKing17WitchKing17

8310

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  You should check for error value returned from r.ParseForm() and use r.PostFormValue() instead.
  
  – Pie 'Oh' Pah
  Nov 20 '18 at 0:30
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  Also note that r.PostFormValue() would be for a PUT, PATCH, or POST. You're sending an http GET method, which is not expended to send any data.
  
  – Slotheroo
  Nov 20 '18 at 0:32
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  How are you sending request data to Go in the first place? The javascript code only send GET request with no data.
  
  – Pie 'Oh' Pah
  Nov 20 '18 at 1:02
  

  
  
  
  

add a comment | 

0

0

0

I have a small Go web-server that displays data to users as they login. The problem I'm trying to achieve is to have the web-page only show certain information when a specific user logs in. For example, when admin logs in there would be a list of admin-only items that they can see on the web-page.

The problem I'm having is for some reason my Go code isn't storing the username in the array that I'm calling, so when I pass it over to the JavaScript it is blank.

Here are the 3 main parts of the code that I'm struggling with:

main.go

package main



import "fmt"



func authHandler(w http.ResponseWriter, r *http.Request) {

    r.ParseForm()

    usernameArray, hasUsername := r.PostForm["j_username"]



    //This line added for debugging purposes

    log.Println("username:", usernameArray[0])



    if hasUsername {

        fmt.Fprintf(w, "%s", usernameArray[0])

    }

}



func main() {

    http.HandleFunc("/getAuth", authHandler)

}

---

javascript.js

Note that this is AngularJS

$scope.init = function() {

    checkAuthentication();

};



checkAuthentication = function() {

    $http.get("/getAuth").then(

    function(response) {

        var username = response.data;



        console.log(username): //Added for debugging purposes



        if (username === "admin") {

            $scope.showAdminOnlyItems = true;

        }

    });

}

---

main.html

<div id="admin-only-items" ng-show="showAdminOnlyItems">

    <hr style="border:1px solid">

    <p style="text-align: center">admin only: </p>

    <div id="adminOnlyButtom">

        <button class="button" data-ng-click="doSomething()">Do something</button>

    </div>

</div>

Again, I only want that div to show up when admin logs in, and Go needs to send the username over to the javascript to verify that. By adding the debugging line in Go and starting the server up, I get this:

2018/11/19 16:28:42 http: panic serving 10.240.49.238:59621: runtime error: 

index out of range

goroutine 26 [running]:

net/http.(*conn).serve.func1(0xc42009f720)

        C:/Go/src/net/http/server.go:1726 +0xd0

panic(0x79f820, 0xe17940)

        C:/Go/src/runtime/panic.go:502 +0x229

main.authHandler(0xc56220, 0xc420135180, 0xc4207a3500)

        D:/src/main.go:346 +0x1d8

So it's clear that the usernameArray is empty, not sure what I did wrong. Can anyone help tell me why the usernameArray is empty in authHandler?

javascript html arrays angularjs go

share|improve this question

edited Nov 20 '18 at 7:51

Flimzy

37.7k96497

asked Nov 19 '18 at 23:56

WitchKing17WitchKing17

8310

I have a small Go web-server that displays data to users as they login. The problem I'm trying to achieve is to have the web-page only show certain information when a specific user logs in. For example, when admin logs in there would be a list of admin-only items that they can see on the web-page.

The problem I'm having is for some reason my Go code isn't storing the username in the array that I'm calling, so when I pass it over to the JavaScript it is blank.

Here are the 3 main parts of the code that I'm struggling with:

main.go

package main



import "fmt"



func authHandler(w http.ResponseWriter, r *http.Request) {

    r.ParseForm()

    usernameArray, hasUsername := r.PostForm["j_username"]



    //This line added for debugging purposes

    log.Println("username:", usernameArray[0])



    if hasUsername {

        fmt.Fprintf(w, "%s", usernameArray[0])

    }

}



func main() {

    http.HandleFunc("/getAuth", authHandler)

}

---

javascript.js

Note that this is AngularJS

$scope.init = function() {

    checkAuthentication();

};



checkAuthentication = function() {

    $http.get("/getAuth").then(

    function(response) {

        var username = response.data;



        console.log(username): //Added for debugging purposes



        if (username === "admin") {

            $scope.showAdminOnlyItems = true;

        }

    });

}

---

main.html

<div id="admin-only-items" ng-show="showAdminOnlyItems">

    <hr style="border:1px solid">

    <p style="text-align: center">admin only: </p>

    <div id="adminOnlyButtom">

        <button class="button" data-ng-click="doSomething()">Do something</button>

    </div>

</div>

Again, I only want that div to show up when admin logs in, and Go needs to send the username over to the javascript to verify that. By adding the debugging line in Go and starting the server up, I get this:

2018/11/19 16:28:42 http: panic serving 10.240.49.238:59621: runtime error: 

index out of range

goroutine 26 [running]:

net/http.(*conn).serve.func1(0xc42009f720)

        C:/Go/src/net/http/server.go:1726 +0xd0

panic(0x79f820, 0xe17940)

        C:/Go/src/runtime/panic.go:502 +0x229

main.authHandler(0xc56220, 0xc420135180, 0xc4207a3500)

        D:/src/main.go:346 +0x1d8

So it's clear that the usernameArray is empty, not sure what I did wrong. Can anyone help tell me why the usernameArray is empty in authHandler?

javascript html arrays angularjs go

javascript html arrays angularjs go

share|improve this question

edited Nov 20 '18 at 7:51

Flimzy

37.7k96497

asked Nov 19 '18 at 23:56

WitchKing17WitchKing17

8310

share|improve this question

edited Nov 20 '18 at 7:51

Flimzy

37.7k96497

asked Nov 19 '18 at 23:56

WitchKing17WitchKing17

8310

share|improve this question

share|improve this question

edited Nov 20 '18 at 7:51

Flimzy

37.7k96497

edited Nov 20 '18 at 7:51

Flimzy

37.7k96497

edited Nov 20 '18 at 7:51

Flimzy

37.7k96497

37.7k96497

asked Nov 19 '18 at 23:56

WitchKing17WitchKing17

8310

asked Nov 19 '18 at 23:56

WitchKing17WitchKing17

8310

asked Nov 19 '18 at 23:56

WitchKing17WitchKing17

8310

8310

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  You should check for error value returned from r.ParseForm() and use r.PostFormValue() instead.
  
  – Pie 'Oh' Pah
  Nov 20 '18 at 0:30
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  Also note that r.PostFormValue() would be for a PUT, PATCH, or POST. You're sending an http GET method, which is not expended to send any data.
  
  – Slotheroo
  Nov 20 '18 at 0:32
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  How are you sending request data to Go in the first place? The javascript code only send GET request with no data.
  
  – Pie 'Oh' Pah
  Nov 20 '18 at 1:02
  

  
  
  
  

add a comment | 

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  You should check for error value returned from r.ParseForm() and use r.PostFormValue() instead.
  
  – Pie 'Oh' Pah
  Nov 20 '18 at 0:30
  

  
  
  
  


• 
  
  
  

  
  2
  

  
  
  
  
  
  

  
  
  Also note that r.PostFormValue() would be for a PUT, PATCH, or POST. You're sending an http GET method, which is not expended to send any data.
  
  – Slotheroo
  Nov 20 '18 at 0:32
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  How are you sending request data to Go in the first place? The javascript code only send GET request with no data.
  
  – Pie 'Oh' Pah
  Nov 20 '18 at 1:02
  

  
  
  
  

1

1

You should check for error value returned from r.ParseForm() and use r.PostFormValue() instead.

– Pie 'Oh' Pah
Nov 20 '18 at 0:30

You should check for error value returned from r.ParseForm() and use r.PostFormValue() instead.

– Pie 'Oh' Pah
Nov 20 '18 at 0:30

2

2

Also note that r.PostFormValue() would be for a PUT, PATCH, or POST. You're sending an http GET method, which is not expended to send any data.

– Slotheroo
Nov 20 '18 at 0:32

Also note that r.PostFormValue() would be for a PUT, PATCH, or POST. You're sending an http GET method, which is not expended to send any data.

– Slotheroo
Nov 20 '18 at 0:32

How are you sending request data to Go in the first place? The javascript code only send GET request with no data.

– Pie 'Oh' Pah
Nov 20 '18 at 1:02

How are you sending request data to Go in the first place? The javascript code only send GET request with no data.

– Pie 'Oh' Pah
Nov 20 '18 at 1:02

add a comment | 

1 Answer
1

active

oldest

votes

1

The first, I can see that you send GET request to server without j_username query param therefore you can not read j_username on server side.

The second, usernameArray is empty slice which is failing while parse j_username. Error index out of range occur when you try to call usernameArray[0].

You should send GET request with j_username like that /getAuth?j_username=admin and modify code from server.

    usernameArray, hasUsername := r.URL.Query()["j_username"]

    //This line added for debugging purposes

    log.Println("debug here :", usernameArray)



    if hasUsername {

        fmt.Fprintf(w, "%s", usernameArray[0])

        return

    }



    // Send an error message to client

    http.Error(w, `missing username`, 500)

share|improve this answer

answered Nov 20 '18 at 2:16

KibGzrKibGzr

1,466610

add a comment | 

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1

The first, I can see that you send GET request to server without j_username query param therefore you can not read j_username on server side.

The second, usernameArray is empty slice which is failing while parse j_username. Error index out of range occur when you try to call usernameArray[0].

You should send GET request with j_username like that /getAuth?j_username=admin and modify code from server.

    usernameArray, hasUsername := r.URL.Query()["j_username"]

    //This line added for debugging purposes

    log.Println("debug here :", usernameArray)



    if hasUsername {

        fmt.Fprintf(w, "%s", usernameArray[0])

        return

    }



    // Send an error message to client

    http.Error(w, `missing username`, 500)

share|improve this answer

answered Nov 20 '18 at 2:16

KibGzrKibGzr

1,466610

add a comment | 

1

The first, I can see that you send GET request to server without j_username query param therefore you can not read j_username on server side.

The second, usernameArray is empty slice which is failing while parse j_username. Error index out of range occur when you try to call usernameArray[0].

You should send GET request with j_username like that /getAuth?j_username=admin and modify code from server.

    usernameArray, hasUsername := r.URL.Query()["j_username"]

    //This line added for debugging purposes

    log.Println("debug here :", usernameArray)



    if hasUsername {

        fmt.Fprintf(w, "%s", usernameArray[0])

        return

    }



    // Send an error message to client

    http.Error(w, `missing username`, 500)

share|improve this answer

answered Nov 20 '18 at 2:16

KibGzrKibGzr

1,466610

add a comment | 

1

1

1

The first, I can see that you send GET request to server without j_username query param therefore you can not read j_username on server side.

The second, usernameArray is empty slice which is failing while parse j_username. Error index out of range occur when you try to call usernameArray[0].

You should send GET request with j_username like that /getAuth?j_username=admin and modify code from server.

    usernameArray, hasUsername := r.URL.Query()["j_username"]

    //This line added for debugging purposes

    log.Println("debug here :", usernameArray)



    if hasUsername {

        fmt.Fprintf(w, "%s", usernameArray[0])

        return

    }



    // Send an error message to client

    http.Error(w, `missing username`, 500)

share|improve this answer

answered Nov 20 '18 at 2:16

KibGzrKibGzr

1,466610

The first, I can see that you send GET request to server without j_username query param therefore you can not read j_username on server side.

The second, usernameArray is empty slice which is failing while parse j_username. Error index out of range occur when you try to call usernameArray[0].

You should send GET request with j_username like that /getAuth?j_username=admin and modify code from server.

    usernameArray, hasUsername := r.URL.Query()["j_username"]

    //This line added for debugging purposes

    log.Println("debug here :", usernameArray)



    if hasUsername {

        fmt.Fprintf(w, "%s", usernameArray[0])

        return

    }



    // Send an error message to client

    http.Error(w, `missing username`, 500)

share|improve this answer

answered Nov 20 '18 at 2:16

KibGzrKibGzr

1,466610

share|improve this answer

share|improve this answer

answered Nov 20 '18 at 2:16

KibGzrKibGzr

1,466610

answered Nov 20 '18 at 2:16

KibGzrKibGzr

1,466610

answered Nov 20 '18 at 2:16

KibGzrKibGzr

1,466610

1,466610

add a comment | 

add a comment | 

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