B4J Question how to implement a server inside a b4j form program?

omarruben · Oct 8, 2023

Hi, I see that we can create web server with b4j but only non UI, what would be the way to give the desktop application web server or communication capabilities ?

on the example at : https://www.b4x.com/android/forum/t...ol-the-desktop-with-your-phone.60887/#content

the program listens UDP,TCP,MQTT... why is not possible to use http? at least to receive commands not to server pages , from a web browser (to avoid create and install a additional app in Android or IOS)

omarruben · Oct 9, 2023

i know is mediocre, but works!!! thanks again everybody :
i leave this as a reference for the future

B4X:

Sub AStream_NewData (Buffer() As Byte)
    
    Dim txt As String = BytesToString(Buffer, 0, Buffer.Length, "UTF8")
    
    Dim components() As String
    components = Regex.Split("\r\n",txt) 
    
    If components(0) = "GET /test HTTP/1.1" Then
        Log("test")
    End If
       
    If components(0) = "GET /autodj HTTP/1.1" Then
        Log("autodj")
        Button8_Click
    End If
    
    Dim html(6) As String
    html(5) = "<html><body><h1>Hello, World!</h1></body></html>" & CRLF
    html(0) = "HTTP/1.1 200 OK" & CRLF
    html(1) = "Content-Type: text/html; charset=utf-8" & CRLF
    html(2) = "Content-Length: " &...

xulihang · Oct 8, 2023

A related thread: https://www.b4x.com/android/forum/threads/can-i-make-a-server-with-ui.154361/

omarruben · Oct 8, 2023

xulihang said:
A related thread: https://www.b4x.com/android/forum/threads/can-i-make-a-server-with-ui.154361/

thanks , I have read a lots of postings and no solution yet

Erel · Oct 9, 2023

Technically you can implement a simple http server. There are several examples in the forum.
This is a good solution if you want to waste your time and create a mediocre server.

A better solution is to separate the server and the UI app and if it sounds difficult then it is still 1000 times simpler than creating a reliable web server.

omarruben · Oct 9, 2023

Erel said:
Technically you can implement a simple http server. There are several examples in the forum.
This is a good solution if you want to waste your time and create a mediocre server.

A better solution is to separate the server and the UI app and if it sounds difficult then it is still 1000 times simpler than creating a reliable web server.

thank you for your answer, I just want to give the app the capability to receive a few commands (not a full server)
following a sample using sockets I have achieve what I want but still can't send a html response:

B4X:

Sub AStream_NewData (Buffer() As Byte)
    Dim txt As String = BytesToString(Buffer, 0, Buffer.Length, "UTF8")
    Dim components() As String
    components = Regex.Split("\r\n",txt)
    If components(0) = "GET /play HTTP/1.1" Then
        Log("play")
    End If
    If components(0) = "GET /autodj HTTP/1.1" Then
        Log("autodj")
        Button8_Click ' plays all music
    End If
    ' send answer (it does not show anything on the browser...why?)'
    Dim  dd As String =$"HTTP/1.1 200 OK
    Content-Type: text/html; charset=utf-8
    Content-Length: 48
    Connection: Closed   
    <html><body><h1>Hello, World!</h1></body></html>"$
    astream.Write(dd.GetBytes("UTF8")) ' <---- whows nothing on the browser
    astream.SendAllAndClose
End Sub

OliverA · Oct 9, 2023

See: https://www.tutorialspoint.com/http/http_responses.htm
1) You have to ensure that all lines end in CRLF
2) You need to leave an empty line between the header(s) and the body

omarruben · Oct 9, 2023

i know is mediocre, but works!!! thanks again everybody :
i leave this as a reference for the future

B4X:

Sub AStream_NewData (Buffer() As Byte)
    
    Dim txt As String = BytesToString(Buffer, 0, Buffer.Length, "UTF8")
    
    Dim components() As String
    components = Regex.Split("\r\n",txt) 
    
    If components(0) = "GET /test HTTP/1.1" Then
        Log("test")
    End If
       
    If components(0) = "GET /autodj HTTP/1.1" Then
        Log("autodj")
        Button8_Click
    End If
    
    Dim html(6) As String
    html(5) = "<html><body><h1>Hello, World!</h1></body></html>" & CRLF
    html(0) = "HTTP/1.1 200 OK" & CRLF
    html(1) = "Content-Type: text/html; charset=utf-8" & CRLF
    html(2) = "Content-Length: " & html(5).Length & CRLF
    html(3) = "Connection: Closed " & CRLF
    html(4) = CRLF

    Dim  dd As String = html(0) & html(1) & html(2) & html(3) & html(4) & html(5)
    astream.Write(dd.GetBytes("UTF8"))
    astream.SendAllAndClose
    
    
End Sub

B4J Question how to implement a server inside a b4j form program?

omarruben

Active Member

omarruben

xulihang

Active Member

omarruben

Active Member

Erel

B4X founder

omarruben

Active Member

OliverA

Expert

omarruben

Active Member

Similar Threads

B4J Question how to implement a server inside a b4j form program?

Active Member

Active Member

Active Member

B4X founder

Active Member

Expert

Active Member

Similar Threads

Privacy & Transparency

Privacy & Transparency