Here is my fragment code procedure TfMain.btnPostClick(Sender: TObject);
var ms: TMemoryStream; s: string;
begin
mmoLog.Clear; s:= '';
ms := TMemoryStream.Create;
try
try
s := idhttpX.Post(edtHost.Text,nil);
mmoLog.Lines.Text := s;
except on E: Exception do ShowMessage(e.ClassName + ':' + e.Message);
end; // try..except
finally ms.Free;
end; // try..finally
end;
var ms: TMemoryStream; s: string;
begin
mmoLog.Clear; s:= '';
ms := TMemoryStream.Create;
try
try
s := idhttpX.Post(edtHost.Text,nil);
mmoLog.Lines.Text := s;
except on E: Exception do ShowMessage(e.ClassName + ':' + e.Message);
end; // try..except
finally ms.Free;
end; // try..finally
end;
Post usually includes sending content, and you're passing nil, so the compiler does not know whether to use the overload with TStream or with TIdMultiPartFormDataStream
thus the "ambiguous" message
I know it will raise a compile error; I explained why
Coz, i never pass compile process, err: E2251, i never know whether this site (yougetsignal.com and portchecker.co) is really support POST method or not. I only evaluate their html i got using Curl, curl.haxx.se. Using web browser, Torch and Firefox , everything is fine, so i assume it support GET method.
But this site wat POST method, not GET method. Can i use GET method to emulate POST method? Here is a part of html code from portchecker.com. <form class="row" id="mainForm" action="/check" method="post">
<div class="large-7 columns">
<div class="row">
<div class="large-7 columns">
<label>Your IP Address</label>
<input type="text" name="target_ip" id="targetIP" value="36.78.221.82" disabled />
</div>
<div class="large-5 columns">
<label>Port Number</label>
<input type="text" name="port" id="portNumber" value="80" required/>
</div>
</div>
<div class="common-ports-list" id="labels-wrapper">
<span class="label info" data-port="80" >HTTP - 80</span>
<span class="label success hidden-on-mobile" data-port="115" >SFTP - 115</span>
<span class="label alert" data-port="25">SMTP - 25</span>
<span class="label info" data-port="8080" >HTTP - 8080</span>
<span class="label alert" data-port="21" >FTP - 21</span>
<span class="label hidden-on-mobile" data-port="22" >SSH - 22</span>
<span class="label warning" data-port="143">IMAP - 143</span>
<span class="label success hidden-on-mobile" data-port="443" >HTTPS - 443</span>
<span class="label alert hidden-on-mobile" data-port="873" >RSYNC - 873</span>
<span class="label info hidden-on-mobile" data-port="110" >POP3 - 110</span>
<span class="label success hidden-on-mobile" data-port="993">IMAPS - 993</span>
</div>
</div>
<div class="large-5 columns btn-wrapper">
<button type="submit" class="button">Check</button>
</div>
</f
<div class="large-7 columns">
<div class="row">
<div class="large-7 columns">
<label>Your IP Address</label>
<input type="text" name="target_ip" id="targetIP" value="36.78.221.82" disabled />
</div>
<div class="large-5 columns">
<label>Port Number</label>
<input type="text" name="port" id="portNumber" value="80" required/>
</div>
</div>
<div class="common-ports-list" id="labels-wrapper">
<span class="label info" data-port="80" >HTTP - 80</span>
<span class="label success hidden-on-mobile" data-port="115" >SFTP - 115</span>
<span class="label alert" data-port="25">SMTP - 25</span>
<span class="label info" data-port="8080" >HTTP - 8080</span>
<span class="label alert" data-port="21" >FTP - 21</span>
<span class="label hidden-on-mobile" data-port="22" >SSH - 22</span>
<span class="label warning" data-port="143">IMAP - 143</span>
<span class="label success hidden-on-mobile" data-port="443" >HTTPS - 443</span>
<span class="label alert hidden-on-mobile" data-port="873" >RSYNC - 873</span>
<span class="label info hidden-on-mobile" data-port="110" >POP3 - 110</span>
<span class="label success hidden-on-mobile" data-port="993">IMAPS - 993</span>
</div>
</div>
<div class="large-5 columns btn-wrapper">
<button type="submit" class="button">Check</button>
</div>
</f
I might be able to find an example
there's an example here which is similar to what you need to do:
http://stackoverflow.com/questions/7762584/post-problems-with-indy-tidhttp
Although you can ignore the parts about SSL. Refer to the accepted answer
http://stackoverflow.com/questions/7762584/post-problems-with-indy-tidhttp
Although you can ignore the parts about SSL. Refer to the accepted answer
the main thing is that you need to pass the content that the URL expects, in the 2nd parameter where you are passing nil instead
From insight, Post(AURL string; ASourceFile: string; ADestEncoding: IIdTexEncoding=nil): string. There are 3 params needed, the third is defaulted to nil. So at least 2 params must be included. I try another way, try only one param and two params with the second param is nil. So error. The error message successfully driving me crazy. Thx for yours help.
http://stackoverflow.com/questions/7762584/post-problems-with-indy-tidhttp is not closed too. no definite answer available.
Is there any ready-to-use solution for multithreaded pings to prevent http://stackoverflow.com/a/12868771/4121488 ?
Or have i to implement all stuff on my own?
I'm having problems with the IMAPClient, one of our customers is getting a RangeError when retrieving mailmessages from an IMAP server (Exchange). When I read the headers (IMAPClient.retrieveHeaders() I get the correct header information, but when I try to download the complete message using Retrieve() I get the RangeError. Using IdLogDebug I found that it does return all the parts of the message and the debug ends with: "C33 OK FETCH completed." So it looks like the message is downloaded completely, and the range error is generated when Indy is parsing the message. Any idea on what this can be? (I'm using Indy 10.6.2.0)
@icegood TIdHTTP already does disconnect in case of socket errors (see the try/except blocks inside of RetreiveHeaders() and around calls to ReadResult()). Putting Content-MD5 in the TIdHTTP header applies the MD5 hash to the entire request body, not to any individual MIME field within the multipart stream, so it can make sense to want to add custom headers on a per-field basis.
@irawancepu based on the HTML you showed, you need to use something more like this instead:
procedure TfMain.btnPostClick(Sender: TObject);
var
params: TStringList;
s: string;
begin
mmoLog.Clear;
s := '';
params := TStringList.Create;
try
params.Add('target_ip=36.78.221.82'); // substitute desired IP
params.Add('port=80'); // substitute desired port
try
s := idhttpX.Post('http://hostname/check', params);
mmoLog.Lines.Text := s;
except
on E: Exception do
ShowMessage(e.ClassName + ':' + e.Message);
end;
finally
params.Free;
end;
end;
procedure TfMain.btnPostClick(Sender: TObject);
var
params: TStringList;
s: string;
begin
mmoLog.Clear;
s := '';
params := TStringList.Create;
try
params.Add('target_ip=36.78.221.82'); // substitute desired IP
params.Add('port=80'); // substitute desired port
try
s := idhttpX.Post('http://hostname/check', params);
mmoLog.Lines.Text := s;
except
on E: Exception do
ShowMessage(e.ClassName + ':' + e.Message);
end;
finally
params.Free;
end;
end;
@mezen I don't know of any ready-made solutions, if you can't find one then you will have to implement it yourself.
@SandroHerbst No, you are not. Indy stopped using batch scripts in Delphi years ago (looks like D2009 was the last version), though it still uses them in C++Builder (for now, they will eventually be phased out). And no, there is no project group for D2010 (never got around to creating one). Just open the 5 Indy packages in the IDE and compile them from there, in this order: IndySystem140, IndyCore140, IndyProtocols140, dclIndyCore140, dclIndyProtocols140, and then install the 2 dcl packages into the IDE.
@Remy Lebeau Everything works as expected now. The 2nd parameter needed in Post method is a TStrings that contains form parameter. I lost this one, never pass compile process. However, the result is of string type, is it nicer if the result is of TStrings type? So there no problem if the result if very big data. What i fear is the response is big so string type is not big enough to hold.
@Remy As you can see from my code before and website i visited, one crucial network guy is to check a port is in open state or just closed. I did port forward some ports on my router to many devices like CCTV. Usually everything okay on high class devices. But now conditions change, many cheap models sold everywhere. They put logo like 'work on cloud directly'. On the other side, port on these cheap devices often get closed if not triggered by visiting website like yougetsignal.com, portchecker.co or canyouuseeme.org. Can i do what these website using Delphi and Indy? So i did not use these web service anymore. It is one of my dreams.
In the past time i have to visit those website in order to check port forwarding status. Now, after your help here, i will use my own program based on Indy 10.6.2.0. I already got good result using Indy. However, i still confused about what and how these website send data to my router so it can determine it's port status. I'm Mikrotik RB1100AHX@ as my router. I will try to sniff these website communication on my ports using WireShark. I will back after same evaluation on these packets. What i want? I want to do status port check my own way. So i do not depend on these website. What happened if these webs going down?
@irawancepu Why not just ask the router itself what its port status is, such as with uPNP? You don't really need to use an external site unless the router has disabled uPNP. You can't simulate a remote site locally. If you are sending a request to an external site, and that site is sending requests to the public ports of your router, you will have to keep doing that, you can't access the public side of the router from the LAN side.
Moreover it occurs in place where connection is checked...
I have anothe question. We have in TIdIOHandlerStack.Connected
ReadFromSource(False, 0, False);
What indy is supposed to read here? Sometimes (vary rarely) my application based on RemObjects SuperTCPServer hangs there as there is nothing to read from server.
@rlebeau Thanks for your answer, I´ve compiled the 5 packages in D2010, it was ok, but when I tried to install the 2 dcl packages, the IDE returns an error "The procedure entry point @Idstack@TIdStackLocalAddressList@GetAddress$qqri could not be located in the dynamic link library IndySystem140.bpl", do I need to remove some files from the old version?
@icegood Indy uses synchronous socket I/O, so the only way to test if a socket is still "connected" is to perform I/O on it. That is what Connected() is doing when it calls ReadFromSource(). It is checking if there is any inbound data on the socket (and if so, the data is read and put in the InputBuffer for later use), using a 0ms timeout and ignoring any disconnect/timeout errors. It should not be hanging if there is no data, unless the OS itself hangs when Indy calls the socket API
select() function (which has been known to happen, despite the timeout - that is an OS issue, not an Indy issue).
@SandroHerbst yes, you need to remove the old version before installling the new version. This is explained in Indy's installation notes
@Remy I'm already doing NAT on my RB1100AHX2. Everything work fine but on this cheap DVR. However, AFTER testing it using web service from site like portchecker.co, yougetsignal.com or canyouseeme.org then it works again. Usually it will work for two or three days before did not work again. Here i need to use one of these web services again. So i think that there are some magic packets this site sends to my router. My router delivers these packet to this cheap DVR. The DVR works again after receiving these magic packets. Here i want to emulate/replicate these magic packets sent by website like portchecker.co by using Indy. Sorry for disturbing you so far. It is a real problem from a network guy facing cheap DVR.
@irawancepu there is no "magic packet" being sent by those sites through the router to the DVR, that is not how those sites work. You apparently don't understand what port scanning does, because there is no actually data sent at all. The sites are merely establishing a TCP connection to the chosen IP/port and then reporting success or failure. If successful, and if the IP/Port happens to be on a NAT router, the router just passes through the connection to the specified LAN server based on its port forwarding rules. That's it. The only thing the DVR sees (if anything) is an inbound TCP connection. You could just connect a TIdTCPClient directly to the DVR to do the same thing. If you want to check the router's port status, use uPNP for that. Or, just connect TIdTCPClient to the desired public IP/port on the router.
@rlebeau ,
your comment makes sense in case if it hangs while calling Readable (ATimeout) in TIdIOHandler.ReadFromSource. But in reality it hangs inside call
LByteCount := ReadDataFromSource(LBuffer); a few lines below. I can imagine next multithread scenario:
1) first thread actively does IO over socket
2) second thread checks for connection and for this moment due activity of first thread Readable returns true.
3) Second thread calls ReadDataFromSource, but for this moment first thread fully has processed data => second thread hangs there.
Remobject's SuperTCPServer depends on Indy library and assumes that Indy10 supports multithread processing.
As for me fix should be in calling of just Readable inside TIdIOHandlerStack.Connected instead of ReadFromSource
@icegood It is not safe for multiple threads to read from a socket at the same time. That includes calling Connected(). For exactly the reason you mentioned - it gets the socket state out of sync. I/O must be synchronized across threads. It is safe for 1 thread to write while another thread reads, that does not need to be synchronized. But having 2+ threads reading, or 2+ threads writing, must be synchronized. On the other hand, 99% of the time there is no need to call Connected() directly, just let Indy raise an exception during normal I/O operations. That being said, having Connected() call Readable() instead of ReadFromSource() is not good enough, since a socket is marked as readable during a graceful disconnect, an actual read is needed to discover the disconnect.