HTTP commands of Dahua NVR
mkleynhans
Junior MemberPosts: 78
Hi guys,
I wanted to ask on here as im not sure whether this will be ok.
We are hoping to implement control of a Dahua NVR which has firmware on it to allow HTTP control of its onscreen display.
The document reckons the command for nav up would be;
http://admin:[email protected]:80/cgi-bin/keyBoardCtrl.cgi?setAction=Up
I have done other devices using HTTP Get type commands by connected to the device on say Port 80 TCP , on the button press,
then linking the command as per below on a button switch case;
CASE 1: SEND_STRING dvDevice_IP,"'GET //cgi-bin/keyBoardCtrl.cgi?setAction=Up HTTP/1.1',$0D,$0A,$0D,$0A"
Then disconnect the connection on release..
I have never had to supply credential before.
How do I go about providing credentials in the connect? at the moment my connects are basic;
DEFINE_CALL 'XBMC CONNECT'
{
IP_CLIENT_OPEN(dvXBMC_IP.port,XBMC_IP_IpAddress,XBMC_IP_Port,IP_TCP)
}
DEFINE_CALL 'XBMC DISCONNECT'
{
IP_CLIENT_CLOSE(dvXBMC_IP.port)
}
Any direction really appreciated..
I wanted to ask on here as im not sure whether this will be ok.
We are hoping to implement control of a Dahua NVR which has firmware on it to allow HTTP control of its onscreen display.
The document reckons the command for nav up would be;
http://admin:[email protected]:80/cgi-bin/keyBoardCtrl.cgi?setAction=Up
I have done other devices using HTTP Get type commands by connected to the device on say Port 80 TCP , on the button press,
then linking the command as per below on a button switch case;
CASE 1: SEND_STRING dvDevice_IP,"'GET //cgi-bin/keyBoardCtrl.cgi?setAction=Up HTTP/1.1',$0D,$0A,$0D,$0A"
Then disconnect the connection on release..
I have never had to supply credential before.
How do I go about providing credentials in the connect? at the moment my connects are basic;
DEFINE_CALL 'XBMC CONNECT'
{
IP_CLIENT_OPEN(dvXBMC_IP.port,XBMC_IP_IpAddress,XBMC_IP_Port,IP_TCP)
}
DEFINE_CALL 'XBMC DISCONNECT'
{
IP_CLIENT_CLOSE(dvXBMC_IP.port)
}
Any direction really appreciated..
0
Comments
The resulting string then needs to be sent as an Authorization header
SEND_STRING dvDVR,"'GET /cgi-bin/keyBoardCtrl.cgi?setAction=Up HTTP/1.1',13,10"
SEND_STRING dvDVR,"'Authorization: Basic ',fnBase64('admin:admin'),13,10,13,10"
Hopefully that should work.
Simon
The two steps are 1) establish the connection socket and 2) once the connection is established - send your message.
So, you need to have a DATA_EVENT[dvXBMC_IP] on the IP port. In that data_event>online: is where you now know the IP Port is connected and it is now time to send your message.
I then took this code and the NVR to site and installed it onto the customers NI3100 and it wouldnt work......
I can get the onscreen display to change by typing the commands into a browser and then manually inputting username and password into the prompt but I just cannot get it to work from Netlinx.
Lots of head scratching and back onto it tomorrow I guess... I am wondering if 3.60 Duet firmware may be the issue as our 3101Sig is on 4.xx.. very strange..
I have checked the router and no VLANs are setup, very odd indeed.. The only difference between the controllers is our office unit a NI-3101-SIG on 192.168.0 range with Duet firmware of 4.1.373 and the customers is a NI-3100 on a 192.168.1 range with firmware of 3.60.453.
PROGRAM_NAME='DAHUA_NVR' DEFINE_DEVICE dvNVR_IP = 0:10:1 dvTP_CCTV_1_1 = 10001:21:1 dvTP_CCTV_1_2 = 10002:21:1 dvTP_CCTV_1_3 = 10003:21:1 dvTP_CCTV_1_4 = 10004:21:1 dvTP_CCTV_1_5 = 10005:21:1 dvTP_CCTV_1_6 = 10006:21:1 dvTP_CCTV_1_7 = 10007:21:1 dvTP_CCTV_1_8 = 10008:21:1 dvTP_CCTV_1_9 = 10009:21:1 dvTP_CCTV_1_10 = 10010:21:1 DEFINE_CONSTANT NVR_IP_IpAddress = '192.168.1.238' NVR_IP_Port = 80 DEFINE_VARIABLE DEV dvTP_NVR[]= { dvTP_CCTV_1_1, dvTP_CCTV_1_2, dvTP_CCTV_1_3, dvTP_CCTV_1_4, dvTP_CCTV_1_5, dvTP_CCTV_1_6, dvTP_CCTV_1_7, dvTP_CCTV_1_8, dvTP_CCTV_1_9, dvTP_CCTV_1_10 } iNVR_IP_Connected = 0 DEFINE_EVENT DATA_EVENT[dvNVR_IP] { ONLINE: { iNVR_IP_Connected = 1 } OFFLINE: { iNVR_IP_Connected = 0 } } BUTTON_EVENT[dvTP_NVR,BUTTON.INPUT.CHANNEL] { PUSH: { fnNVRIPConnect() SWITCH(BUTTON.INPUT.CHANNEL) { CASE 1: { //Up SEND_STRING dvNVR_IP,"'GET /cgi-bin/keyBoardCtrl.cgi?setAction=Up HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 2: { //Down SEND_STRING dvNVR_IP,"'GET /cgi-bin/keyBoardCtrl.cgi?setAction=Down HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 3: { //Left SEND_STRING dvNVR_IP,"'GET /cgi-bin/keyBoardCtrl.cgi?setAction=Left HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 4: { //Right SEND_STRING dvNVR_IP,"'GET /cgi-bin/keyBoardCtrl.cgi?setAction=Right HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 5: { //Enter SEND_STRING dvNVR_IP,"'GET /cgi-bin/keyBoardCtrl.cgi?setAction=Enter HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 6: { //Escape SEND_STRING dvNVR_IP,"'GET /cgi-bin/keyBoardCtrl.cgi?setAction=Escape HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 11: { //Camera 1 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=0 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 12: { //Camera 2 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=1 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 13: { //Camera 3 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=2 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 14: { //Camera 4 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=3 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 15: { //Camera 5 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=4 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 16: { //Camera 6 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=5 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 17: { //Camera 7 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=6 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 18: { //Camera 8 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=7 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 19: { //Camera 9 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=8 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 20: { //Camera 10 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=9 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 21: { //Camera 11 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=10 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 22: { //Camera 12 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=11 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 23: { //Camera 13 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=12 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 24: { //Camera 14 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=13 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 25: { //Camera 15 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=14 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 26: { //Camera 16 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split1&group=15 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 31: { //Split4 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split4&group=0 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 32: { //Split9 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split9&group=0 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } CASE 33: { //Split16 SEND_STRING dvNVR_IP,"'GET /cgi-bin/split.cgi?action=setMode&channel=0&mode=Split16&group=0 HTTP/1.1',13,10" SEND_STRING dvNVR_IP,"'Authorization: Basic ',fnBase64('remote:remote2017'),13,10,13,10" } } } RELEASE: { fnNVRIPDisconnect() } } DEFINE_FUNCTION fnNVRIPConnect() { IP_CLIENT_OPEN(dvNVR_IP.port,NVR_IP_IpAddress,NVR_IP_Port,IP_TCP) } DEFINE_FUNCTION fnNVRIPDisconnect() { IP_CLIENT_CLOSE(dvNVR_IP.port) } DEFINE_FUNCTION CHAR[255] fnBase64 (CHAR Source[]) { LOCAL_VAR CHAR Uncode[255] // Password protected sites require that the LOCAL_VAR CHAR Coded[255] // username & password get encoded together in LOCAL_VAR CHAR Munch[3] // Base64 format. Don't know what Base64 is? LOCAL_VAR CHAR Chew[4] // Neither did I until I looked at LOCAL_VAR INTEGER Step // http://freesoft.org/CIE/RFC/2065/56.htm // and http://freesoft.org/CIE/RFC/1521/7.htm Coded = '' Chew = ' ' Uncode = Source WHILE (LENGTH_STRING(Uncode) >= 3) { Munch = GET_BUFFER_STRING(Uncode,3) Chew[1] = Munch[1] Chew[1] = Chew[1] / 4 Chew[2] = ((Munch[1] * 16) BAND $30) Chew[2] = Chew[2] + ((Munch[2] / 16) BAND $F) Chew[3] = ((Munch[2]*4) BAND $3C) Chew[3] = Chew[3] + ((Munch[3] / 64) BAND $3) Chew[4] = Munch[3] BAND $3F Coded = "Coded,Chew" } SELECT { ACTIVE (LENGTH_STRING(Uncode) = 2): { Munch = "GET_BUFFER_STRING(Uncode,2)" Chew[1] = Munch[1] Chew[1] = Chew[1] / 4 Chew[2] = ((Munch[1] * 16) BAND $30) Chew[2] = Chew[2] + ((Munch[2] / 16) BAND $F) Chew[3] = ((Munch[2]*4) BAND $3C) Chew[4] = 64 Coded = "Coded,Chew" } ACTIVE (LENGTH_STRING(Uncode) = 1): { Munch = GET_BUFFER_STRING(Uncode,1) Chew[1] = Munch[1] Chew[1] = Chew[1] / 4 Chew[2] = ((Munch[1] * 16) BAND $30) Chew[3] = 64 Chew[4] = 64 Coded = "Coded,Chew" } } FOR (Step = 1;Step <= LENGTH_STRING(Coded);Step++) { SELECT { ACTIVE (Coded[Step] <= 25): Coded[Step] = Coded[Step] + 65 ACTIVE (Coded[Step] <= 51): Coded[Step] = Coded[Step] + 71 ACTIVE (Coded[Step] <= 61): Coded[Step] = Coded[Step] - 4 ACTIVE (Coded[Step] = 62): Coded[Step] = '+' ACTIVE (Coded[Step] = 63): Coded[Step] = '/' ACTIVE (coded[Step] = 64): Coded[Step] = '=' } } RETURN Coded }Firmware on the NVR might be a possibility but I agree not he master. I've come across several devices over the years that would not work because of the firmware variant used. Heck even when AMX came out with that audio system whose name escapes me they changed the communication baud rate between versions with out documenting that fact so the NVR could have changed many things from port or going from HTTP/1.0 to 1.1 or vice verse between versions.
Line 5 (14:17:29):: HTTP/1.1 401 Unauthorized$0D$0AWWW-Authenticate: Digest realm="Login to 1L04659PAMZVS6J",qop="auth",nonce="1659866321",opaque="9ceb3a49
Does this mean digest type authentication? I defintately had it working perfectly in our office - this is driving me nuts =/
Have parsed digest info and sent back the correct credential and am controlling perfectly again...
DEFINE_FUNCTION fnParseNVRBuffer() { WHILE (FIND_STRING (CnvrBuffer, 'WWW-Authenticate: Digest realm="', 1)) { REMOVE_STRING (CnvrBuffer, 'WWW-Authenticate: Digest realm="', 1) cRealm=LEFT_STRING(CnvrBuffer, FIND_STRING(CnvrBuffer, '",', 1) -1) cRealmActual = "'"',cRealm,'"'" REMOVE_STRING (CnvrBuffer, 'qop="', 1) cQop=LEFT_STRING(CnvrBuffer, FIND_STRING(CnvrBuffer, '",', 1) -1) REMOVE_STRING (CnvrBuffer, 'nonce="', 1) cNonce = LEFT_STRING(CnvrBuffer, FIND_STRING(CnvrBuffer, '",', 1) -1) REMOVE_STRING (CnvrBuffer, 'opaque="', 1) cOpaque = LEFT_STRING(CnvrBuffer, FIND_STRING(CnvrBuffer, '"', 1) -1) A1 = "NVR_Username,':',cRealm,':',NVR_Password" A2 = "'GET:',cURI" fnGenRandom() MD5(A1,HA1) MD5(A2,HA2) TEMP = "HA1,':',cNonce,':',cQop,':',HA2" MD5("HA1,':',cNonce,':00000001:',cCNonce,':',cQop,':',HA2",Response) CLEAR_BUFFER CnvrBuffer fnSendResponse() } }I know this is an old thread but it's the only place I could find the http commands for navigation on the NVR. However I've been unable to get the above navigation commands to work on the Dahua NVR I have. None of the navigation commands work but the commands for switching cameras work. If I send a "Right" command I get an Error Bad Request! response which implies the NVR doesn't understand the command.
Can anyone help?
Hi,
As in the previous post - I know it's an old thread, but I have also a Dahua NVR to control. The way to acquire information necessary for digest authorization posted by @mkleynhans is very helpful, I have, however, one problem. After NVR replies with all the stuff like cRealm, qop, nonce etc., it closes the connection and I can't respond to it with the appropriate credentials. If I open the connection again and send the string with the credentials from the previous session, I receive a response as follows:
Line 401 2021-04-02 (08:57:18):: HTTP/1.1 401 Unauthorized$0D$0AConnection: close$0D$0AContent-type: text/plain;charset=utf-8$0D$0AContent-Length: 27$0D$0A$0D$0AError$0D$0AInvalid Authority!$0D$0A
Can anyone give a piece of advice how to hadle it?
Best regards,
If you can secure the control API, we will write a module for it. Their support channels keep sending me to Sales for the document and since I am not a customer, they have not been willing to share.
@MichalMoraszczyk you need to use MD5 encryption to send the correct digest credentials it has sent you back to the unit. I had to do digest auth recently for a Sony unit that wouldn't work in any other way.
Have a look at this
[https://en.wikipedia.org/wiki/Digest_access_authentication#Example_with_explanation]
It's actually pretty straightforward - and there is a MD5 include kicking around already if you do a search.
Simon
Lots of http goodness to be found here
https://github.com/DavidVine/amx-util-library
@DavidVine shout out!
Well done Ian that's the one! For all MD5 requirements - very useful if you ever need to write a PJLink module.
@sling100 - thank you for your response. I'm using md5 encryption (btw - taken from github repository mentioned by Ian). @HARMAN_icraigie - thank you for the link to the repository.
My current situation is following: I send the request to a NVR (without credentials) and I receive a response '401 Unauthorized', which triggers a following piece of code (under 'string' part of data_event):
string:
{
send_string 0,sCameraRecorderBuffer;
if(find_string(sCameraRecorderBuffer,'401 Unauthorized',1))
{
if(find_string(sCameraRecorderBuffer, 'WWW-Authenticate: Digest realm="', 1)) { remove_string(sCameraRecorderBuffer, 'WWW-Authenticate: Digest realm="', 1); cRealm = left_string(sCameraRecorderBuffer, find_string(sCameraRecorderBuffer, '",', 1) -1); cRealmActual = "'"',cRealm,'"'"; remove_string (sCameraRecorderBuffer, 'qop="', 1); cQop = left_string(sCameraRecorderBuffer, find_string(sCameraRecorderBuffer, '",', 1) -1); remove_string (sCameraRecorderBuffer, 'nonce="', 1); cNonce = left_string(sCameraRecorderBuffer, find_string(sCameraRecorderBuffer, '",', 1) -1); remove_string (sCameraRecorderBuffer, 'opaque="', 1); cOpaque = left_string(sCameraRecorderBuffer, find_string(sCameraRecorderBuffer, '"', 1) -1); sResponse = fnCameraRecorderResponse(); CLEAR_BUFFER sCameraRecorderBuffer; fnStringToCameraRecorder(); } } }Function fnCameraRecorderResponse() which is used to build a response using the credentials received in the response from NVR looks as follows:
define_function char[256] fnCameraRecorderResponse()
{
stack_var char sTempResponse[256];
A1 = "sCameraRecorderUserName,':',cRealm,':',sCameraRecorderUserPass"; A2 = "'GET:',cURI"; HA1 = md5(A1); HA2 = md5(A2); cCNonce = fnGenerateCNonce(); //TEMP = "HA1,':',cNonce,':',cQop,':',HA2" sTempResponse = md5("HA1,':',cNonce,':00000001:',cCNonce,':',cQop,':',HA2"); return sTempResponse;}
Whereas function fnGenerateCNonce() which calculates CNonce parameter looks as follows:
define_function char[20] fnGenerateCNonce()
{
local_var char cCnonce[20];
local_var char sTempHex[5];
stack_var integer nLoopCounter;
cCnonce = ''; for(nLoopCounter = 1; nLoopCounter < 5; nLoopCounter++) { sTempHex = itohex(random_number(256)); cCnonce = "cCnonce,sTempHex"; } return cCnonce;}
Finally, function fnStringToCameraRecorder() which is responsible for sending the request with credentials was built in a following way:
define_function fnStringToCameraRecorder()
{
if(!nCameraRecorderIsOnline)
{
ip_client_open(dvCameraRecorder.port,sCameraRecorderIPAddress,nCameraRecorderIPPort,IP_TCP);
}
wait_until(nCameraRecorderIsOnline) { send_string dvCameraRecorder,"'GET ',cURI,' HTTP/1.1',$0D,$0A,'Host: ',sCameraRecorderIPAddress,$0D,$0A"; send_string 0,"'GET ',cURI,' HTTP/1.1',$0D,$0A,'Host: ',sCameraRecorderIPAddress,$0D,$0A"; send_string dvCameraRecorder,"'Authorization: Digest username:="',sCameraRecorderUserName,'", realm="',cRealm,'", nonce="',cNonce,'", uri="',cURI,'", qop=auth, nc=00000001, cnonce="',cCnonce,'" , response="',sResponse,'", opaque="',cOpaque,'"',$0D,$0A,$0D,$0A"; send_string 0,"'Authorization: Digest username:="',sCameraRecorderUserName,'", realm="',cRealm,'", nonce="',cNonce,'", uri="',cURI,'", qop=auth, nc=00000001, cnonce="',cCnonce,'" , response="',sResponse,'", opaque="',cOpaque,'"',$0D,$0A,$0D,$0A"; } }}
The problem was that after triggering this function in the Diagnostics window I saw onerror event and a message that the string couldn't be sent (I don't remember how it looked precisely, but it was something like this). It looked like AMX master hadn't managed to send the string before the connection with NVR closed.
I rebuilt the latter function to send the request with credentials, so that it waits until the connection is closed, then reopens it and sends the string as above. The response from NVR is in this case as below:
Line 401 2021-04-02 (08:57:18):: HTTP/1.1 401 Unauthorized$0D$0AConnection: close$0D$0AContent-type: text/plain;charset=utf-8$0D$0AContent-Length: 27$0D$0A$0D$0AError$0D$0AInvalid Authority!$0D$0A
It looks like the credentials from the previous session are not valid anymore.
Perhaps someone has had a similar issue (or can see a bug in one of the functions).
Thanks in advance for any advice.
Best regards.
HTTP is not a maintained connection. You need to build and cache the packet, open the connection then send the cached packet once the connection is online.
Sometimes you can sneak in the next message if the connection is still open from the previous message so the packet can be sent directly instead of being cached if the connection is still online.