HTTP Basic Authentication with the AL HttpClient

8th May 2019 Dan Kinsella 10 Comments

Business Central and the AL language have made web service code much easier with the HttpClient and Json types available. Handling the HTTP Authorization header is easier too with the TempBlob table, which can now encode the basic authentication string using base64.

See below for an example of how to add a basic authorisation header to the AL HttpClient:

procedure AddHttpBasicAuthHeader(UserName: Text[50]; Password: Text[50], var HttpClient : HttpClient);
var
  AuthString: Text;
  TempBlob: Record TempBlob temporary;
begin
  AuthString := STRSUBSTNO('%1:%2, UserName, Password);
  TempBlob.WriteTextLine(AuthString);
  AuthString := TempBlob.ToBase64String();
  AuthString := STRSUBSTNO('Basic %1', AuthString);
  HttpClient.DefaultRequestHeaders().Add('Authorization', AuthString);
end;

Update 2019-07-04: Thanks to Arend-Jan Kauffmann commenting on LinkedIn to point out there is an even easier way to get the Base64 encoding done using Codeunit 10 “Type Helper”:

procedure AddHttpBasicAuthHeader(UserName: Text[50]; Password: Text[50], var HttpClient : HttpClient);
var
  AuthString: Text;
  TypeHelper: "Type Helper";
begin
  AuthString := STRSUBSTNO('%1:%2, UserName, Password);
  AuthString := TypeHelper.ConvertValueToBase64(AuthString);
  AuthString := STRSUBSTNO('Basic %1', AuthString);
  HttpClient.DefaultRequestHeaders().Add('Authorization', AuthString);
end;

10 thoughts on “HTTP Basic Authentication with the AL HttpClient”

Varun says:

18th July 2019 at 11:39 am

Hi after adding the above details, i am getting misused header name error while sending the details, any idea about this.

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Dan Kinsella says:

18th July 2019 at 12:16 pm

Hi Varun, are you able to share a code snippet showing how you create the auth string and add the header? Also which version of NAV/BC are you working on? I recall a similar error when using the .NET libraries in NAV as it doesn’t like you directly adding an Authorisation header to the HTTPRequest, and requires the use of a specific function to add credentials.

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Sven Francke says:

26th August 2019 at 8:21 am

In BC ocktober 2019 release (version 15) its looks like the .ConvertValueToBase64 is removed from the codeunit 10 (Type Helper). Do you know if this procedure has been just moved or completly removed?

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1. Sven Francke says:
  
  27th August 2019 at 6:04 am
  
  Thanks to Fernando Tornero (@ github), I found the same procedure in a new codeunit “Base64 Helpers” (codeunit 4110)
  
  Reply
  1. Dan Kinsella says:
    
    27th August 2019 at 7:27 am
    
    Thanks Sven, much appreciated!
    
    Reply
  2. nicolai magnussen says:
    
    10th March 2023 at 10:38 am
    
    And thanks to you, you helped me
    But now it looks like it is named Base64 Convert
    
    And it would be typeHelper.ToBase64
    
    Reply
steven says:

16th December 2020 at 8:08 am

Thanks, this is very helpful.

I submit an update for V17 of BC :
procedure AddHttpBasicAuthHeader(UserName: Text[50]; Password: Text[50]; var HttpClient: HttpClient);
var
AuthString: Text;
Base64Helpers: Codeunit “Base64 Convert”;
begin
AuthString := STRSUBSTNO(‘%1:%2’, UserName, Password);
AuthString := Base64Helpers.ToBase64(AuthString);
AuthString := STRSUBSTNO(‘Basic %1’, AuthString);
HttpClient.DefaultRequestHeaders().Add(‘Authorization’, AuthString);
end;

Hope this helps.

Reply
1. Dan Kinsella says:
  
  17th December 2020 at 9:19 am
  
  Thanks Steven, updates very much appreciated!
  
  Reply
2. rtech says:
  
  25th October 2022 at 1:37 pm
  
  Hi Steven/Dan – I am trying to generate a base64 string from the codeunit and passing it in my authstring. If I paste the AuthString generated by postman API, the API response is succesful. Below are both the AuthStrings. Any suggestions/ideas?
  
  The first one is via POSTMAN, second one via base64 codeunit in AL. I am working on the latest version of BC SaaS
  
  Basic dGVzdF9kcEIxSDV4Y3V0eWNkam1VZVk0REJDSE4wQm96YlN6bExPOg==
  
  Basic dGVzdF9kcEIxSDV4Y3V0eWNkam1VZVk0REJDSE4wQm96YlN6bExPICA=
  
  Reply
James says:

13th December 2022 at 5:47 am

Thanks for the hints Dan.

Reworked in 2022
“`
[NonDebuggable]
local procedure AddBasicAuthHeader(HMGSetup: Record vfs_dp1_HMGSetup; var ReqHeaders: HttpHeaders)
var
Base64: Codeunit “Base64 Convert”;
Password: Text;
AuthString: Text;
AuthStringTxt: Label ‘%1:%2’, Locked = true;
AuthHeaderTxt: Label ‘Basic %1’, Locked = true;
AuthHeaderLbl: Label ‘Authorization’, Locked = true;
begin
IsolatedStorage.Get(HMGSetup.”Password GUID”, DataScope::Module, Password);
AuthString := STRSUBSTNO(AuthStringTxt, HMGSetup.”User ID”, Password);
AuthString := Base64.ToBase64(AuthString);
AuthString := STRSUBSTNO(AuthHeaderTxt, AuthString);
ReqHeaders.Add(AuthHeaderLbl, AuthString);
end;

“`

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