Client for MPD

[mamuen]

Hi,
danke an alle.

Die Info war gut, denn MPD setzt für die Kommunuikation zwischen Client und
Server TCP als Übertragungsprotokoll ein. Somit kann ich vom Sofa aus meine
Stereoanlage fernsteuern und kann die Musik genießen ohne mich bewegen zu
müssen.

Gruß Mamuen

[specci48]

Originally Posted by alfcen

Hier sind es 8 Stunden spaeter als bei Euch

... netter Trick: man zieht nach Okinawa und ist dann seiner (Ursprungs-)Zeit immer ein wenig voraus ...

[mamuen]

Originally Posted by specci48

... netter Trick: man zieht nach Okinawa und ist dann seiner (Ursprungs-)Zeit immer ein wenig voraus ...

Ok, Ok man kanns ja mal versuchen ;-)

Ich hab jetzt meine ersten gehversuche hinter mir. Auf meinem LinuxSoundserver
läuft der MPD-Dämon und mittels TCPDump überwache ich die WLanschnittstelle.

Nachdem ich eine Verbindung mittels meines Progs aufzubauen versuche, sehe
ich in TCPDump ein von mir gesendetes IP-Paket. Dieses wird mehrmals gesendet
aber es kommt zu keinem Verbindungsaufbau (3-Wegehandshake bei TCP). Die
Firewall ist ausgeschaltet. Per Webbrowser bekomme ich aber Zugriff auf die
Linuxbüchse.

Tja, da bleibt nur noch die eigene Unfähigkeit (Programmierkunst) übrig.
Ich versuch mal mein Prog anzuhängen und hoffe, dass einer einen Fehler
findet.

Gruß Mamuen

[mamuen]

Hi,

ich habe eine kleine Erfolgsmeldung zu berichten, nachdem ich den Port von 6600
auf 80 geändert habe, bekam ich keine Fehlermeldung mehr (Resssource konnte
nicht mehr gefunden werden). Statt dessen bekam ich natürlich Fehlermeldungen
von meinem Webserver.

Werde wohl noch ein Bischen mit dem Protokoll von MPD experimentieren
müssen.

Gruß mamue

[brathbone]

Forgive the response in english. I don't speak German, but I may be able to help.

MPD server listens on TCP port 6600

When you send commands, you must append CHR(13) to the end of the command.

Responses from MPD server will also be terminated with CHR(13)

I don't have MPD, so code below is untested.

Try something like this:

Sub Globals
Dim IP(0) As String
Dim bufferbits(0) As byte
End Sub

Sub ButtonConnect_Click

Dim IP(0) As String
IP() = Client.GetIP(textboxip.Text)
'client = network.dll client
client.Connect(IP(0),6600)
'stream = binaryfile object
stream.New1(client.GetStream,false)
label1.Text = "Connection established."
timer1.Enabled = true
'//issue the "next" command
stream.WriteBytes (stream.StringToBytes("next" & CHR(13)) )
End Sub

Sub Timer1_Tick
If client.DataAvailable = true Then
Dim bufferbits(4096) As byte
count = stream.ReadBytes(bufferbits(),4096)
buffer = bit.BytesToString(bufferbits(),0,count)
'show server response
label1.Text = buffer
End Sub

Best wishes,

[mamuen]

Hi brathbone,

Thanke you for your interest. I have check it at
http://mpd.wikia.com/wiki/MusicPlaye...rotocolOutline

There you can read:
"The client transmits a command sequence, terminated by a newline."
"Each server response ends with a completion code. There are two codes: OK and ACK."

My problem is now, the prog. reads only about 33600 bytes not the whole stream.
By the next trasmitted newline the prog. will receive the rest.


Sub Globals
'Declare the global variables here.
Dim bufferbits(0) As byte
End Sub

Sub App_Start
Form1.Show
End Sub

Sub btnSetSRV_Click
bit.New1
client.New1
client.Connect ("192.168.200.1",6600)
stream.New1(client.GetStream,false)
Do While client.DataAvailable = false
Loop
Dim bufferbits(128) As byte
count = stream.ReadBytes(bufferbits(),128)
buffer = bit.BytesToString(bufferbits(),0,count)
txtAntwort.Text = buffer
Label5.Text = "Connected to 192.168.200.1:6600"
Form2.Show
End Sub

Sub btnSend_Click
stream.WriteBytes (stream.StringToBytes(txtBefehl.Text & Chr(10)) )
timer1.Enabled = true
End Sub

Sub Timer1_Tick
If client.DataAvailable = true Then
Dim bufferbits(102400) As byte
count = stream.ReadBytes(bufferbits(),102400)
buffer = bit.BytesToString(bufferbits(),0,count)
buffer = StrReplace (buffer,Chr(10),crlf) 'linefeed to crlf
txtAntwort.Text = buffer
txtcount.Text = count
End If
timer1.enabled = false
txtBefehl.Focus
End Sub

Sub btnExit_Click
client.Close
AppClose
End Sub



Best wishes, Mamuen

[brathbone]

mamuen,

Thanks for reminding me that I have to be more careful about waiting for all the data to arrive.

So let's say the server sends two commands like:

220 then a bunch of other text & CRLF
240 something else & CRLF


We might get "220 then" when we check for incoming data, and then we might get "a bunch of other text" & chr(13) & chr(10) & "240 Something el"
and then might get "se" & chr(13) & chr(10) on our next check.

The trick here is going to be to use a global variable to store our incomplete commands between checking for data. Then when we check for data, we check to see if there is a terminator in it (chr(13) & chr(10)) using something like:

If StrIndexOf(stringbuffer,chr(13) & chr(10),0) > -1

We can't assume that the terminator is the last part of our data, since we may have received part of the next message as well, so if there is a terminator, take everything before the terminator, append it to whatever may have come in before (our global variable) and then act accordingly. Of course we need to look for additional terminators or partial data before proceeding.

If we don't have a terminator, then append the data to our global variable. I don't have this code written in Basic4PPC yet, but here is pseudo-code based on what my REALbasic code does:

count = stream2.ReadBytes(bufferbits(),8192)
stringbuffer = bit.BytesToString(bufferbits(),0,count)

'//look for a terminator in our new data
i = StrIndexOf(stringbuffer,CHR(13) & CHR(10),0)

if i > -1 then
'//loop though and process commands until we run out of terminators
do while i > -1

'//parse out everything before the first terminator
'//append it to any existing data in our global variable
'//process the command

'//look for additional terminators in existing data
i = StrIndexOf(stringbuffer,CHR(13) & CHR(10),i)
loop

else
'//no terminator in this batch of data
'//append text to global variable and wait for more data.

end if

hope that helps,

[mamuen]

Hi brathbone,

your way i think is the clean way. I found a other solution (quick and dirty), but it works. The endstring of transmision is always "OK"+crlf.


endstr = 0
Dim bufferbits(4096) As byte
If client.DataAvailable = true Then
Do
count = stream.ReadBytes(bufferbits(),4096)
buffer = bit.BytesToString(bufferbits(),0,count)
buffer = StrReplace (buffer,Chr(10),crlf) 'linefeed to crlf

If SubString (buffer,StrLength(buffer)-4,2)="OK" Then
endstr = 1
Else If SubString (buffer,0,3)="ACK" Then
endstr = 2
End If

txtAntwort.Text = txtAntwort.Text & buffer
Loop While endstr = 0
txtcount.Text = endstr
End If



Regards manuen