IndySockets/Indy

Indy - Internet Direct

Sergey

@icegood

@rlebeau, i've just checked change of size via Debug Watch . As i said above it happens only in case when my stream position is at the end.

I have another question, my HTTP protocol has KeepAlive=True and i see that in this case no disconnection happens:

if not Response.KeepAlive then begin
// TODO: do not disconnect if hoNoReadMultipartMIME is in effect
// TODO: do not disconnect if hoNoReadChunked is in effect
Disconnect;
end;

but i wonder whether is it a good idea to disconnect in case when socket error occurs? E.g. 'connection reset by peer'?

Sergey

@icegood

@rlebeau : "but there is currently no option to add custom headers to TIdMultipartFormDataStream fields, sorry."
we don't need that , do we? I've added MD5 header directly to TIdHTTP.CustomHeader and it works for me

irawancepu

@irawancepu

Using Delphi 2007, Indy 10 version 10.6.2.0, i got : E2251: ambiguous overloaded call to 'Post'. How to resolve this?

irawancepu

@irawancepu

Whew, there are 8 overloaded functions in idHttp.pas What i wanto to do actually is simply read response from portchecker.co. From there i can decide my port forwarding correctly or not. Many combination on Post methods are possible. Depend on STRING_IS_ANSI directive too. Too hard for me.

davidpn

@davidpn

you could just read the return value of the version of Post that returns a value

you can use code completion to determine which overloads are applicable

I mean code insight

irawancepu

@irawancepu

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;

davidpn

@davidpn

does the server support only Post for that URL? Are you able to use a Get?

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

irawancepu

@irawancepu

This error raise up on compile process. From html text the server produces, yes this server support POST method.

davidpn

@davidpn

I asked if it also supports Get

I know it will raise a compile error; I explained why

irawancepu

@irawancepu

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.

davidpn

@davidpn

ok.. so use Get instead

irawancepu

@irawancepu

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

davidpn

@davidpn

yes, it will require Post. It also means you'll need to pass the content it expects when you call Post. You're passing nil, which means no content

irawancepu

@irawancepu

problem is, i never pass compile process. how can i send the data it needs then? i will try using other delphi version. maybe D2007 is too old. very hard to keep many versions.

davidpn

@davidpn

it has been a while since I have done that with Indy, perhaps @rlebeau can help when he is around

I might be able to find an example

davidpn

@davidpn

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

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

mezen

@mezen

Sound like a chicken or egg problem: You cant compile because you dont send data, but you cant send data, because you cant compile...

irawancepu

@irawancepu

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.

irawancepu

@irawancepu

http://stackoverflow.com/questions/7762584/post-problems-with-indy-tidhttp is not closed too. no definite answer available.

davidpn

@davidpn

there is a definite answer

mezen

@mezen

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?

Jos de Bruijn

@josdebr_twitter

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)

Remy Lebeau

@rlebeau

@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.

Remy Lebeau

@rlebeau

@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;

@mezen I don't know of any ready-made solutions, if you can't find one then you will have to implement it yourself.

Remy Lebeau

@rlebeau

@josdebr_twitter what is the EXACT error message? What does the call stack look like when the error occurs?

SandroHerbst

@SandroHerbst

Hi, I need to update my Indy in Delphi 2010, I´ve download the SVN Repo, and in trunk/lib there are a lot of batch files to compile it, but there is not a Full_D2010.bat or a Indy140.groupproj. Am I searching in the wrong place? Thanks

Remy Lebeau

@rlebeau

@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.

irawancepu

@irawancepu

@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 Lebeau

@rlebeau

@irawancepu TStrings takes up more memory than a single string, and would scatter the list entries all over memory as well. Most people don't need HTTP results in a TStrings, a string suffices. However, Post() does have other overloads to return data using TStream instead.

irawancepu

@irawancepu

@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.

Remy Lebeau

@rlebeau

@irawancepu Indy lets you do just about anything, if you put in the work for it. What EXACTLY do you need to do?

irawancepu

@irawancepu

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?

Remy Lebeau

@rlebeau

@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.

Jos de Bruijn

@josdebr_twitter

@rlebeau the exact error message is: "ERangeError raised: Range check error". I get the error after I call "IMAPClient.Retrieve(i, Msg)", I do not have a complete call stack, because I cannot reproduce the error locally.

Sergey

@icegood

Remy wrote : @icegood TIdHTTP already does disconnect in case of socket errors....
OK. But socket error might also occur while sending request, might not it?

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.

SandroHerbst

@SandroHerbst

@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?

Remy Lebeau

@rlebeau

@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

SandroHerbst

@SandroHerbst

@rlebeau Thanks again, now it´s ok!

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