I am using Httconnection for connecting to webserver , somtimes request fails causing
EOFException when calling httpconnection.getResponseCode().
I am setting the following headers while making the connection
HttpConnection httpconnection = (HttpConnection) Connector.open(url.concat(";interface=wifi"));
httpconnection.setRequestProperty("User-Agent","Profile/MIDP-2.0 Configuration/CLDC-1.0");
httpconnection.setRequestProperty("Content-Language", "en-US");
I am closing all the connections after processing the request properly.Is this exception is due to exceeding max connections.
It's an internal server error, which return status code 500 in response.
This may be caused by incorrect request, but as well server code or overload may be the reason.
If you have access to server, check event logs.
See also
500 EOF when chunk header expected
Why might LWP::UserAgent be failing with '500 EOF'?
500 EOF instead of reponse status line in perl script
Apache 1.3 error - Unexpected EOF reading HTTP status - connectionreset
Error 500!
UPDATE On the other hand, if it's not response message, but a real exception, then it may be simply a bug, just like in old java
And workaround may be putting getResponseCode() inside of try/catch and call second time on exception:
int responseCode = -1;
try {
responseCode = con.getResponseCode();
} catch (IOException ex1) {
//check if it's eof, if yes retrieve code again
if (-1 != ex1.getMessage().indexOf("EOF")) {
try {
responseCode = con.getResponseCode();
} catch (IOException ex2) {
System.out.println(ex2.getMessage());
// handle exception
}
} else {
System.out.println(ex1.getMessage());
// handle exception
}
}
Talking by connections number limit, read
What Is - Maximum number of simultaneous connections
How To - Close connections
Using HTTPTransportSE, write this before invoke the method "call"
ArrayList<HeaderProperty> headerPropertyArrayList = new ArrayList<HeaderProperty>();
headerPropertyArrayList.add(new HeaderProperty("Connection", "close"));
transport.call(SOAP_ACTION, envelope, headerPropertyArrayList);
Related
I use aws-neptune.
And I try to implement my queries as transactional(with sessionClient like: https://docs.aws.amazon.com/neptune/latest/userguide/access-graph-gremlin-sessions.html). But when I try to implement it, closing client throws exception. There is similar issue like my case: https://groups.google.com/g/janusgraph-users/c/N1TPbUU7Szw
My code looks like:
#Bean
public Cluster gremlinCluster()
{
return Cluster.build()
.addContactPoint(GREMLIN_ENDPOINT)
.port(GREMLIN_PORT)
.enableSsl(GREMLIN_SSL_ENABLED)
.keyCertChainFile("classpath:SFSRootCAG2.pem")
.create();
}
private void runInTransaction()
{
String sessionId = UUID.randomUUID().toString();
Client.SessionedClient client = cluster.connect(sessionId);
try
{
client.submit("query...");
}
finally
{
if (client != null)
{
client.close();
}
}
}
And exception is:
INFO (ConnectionPool.java:225) - Signalled closing of connection pool on Host{address=...} with core size of 1
WARN (Connection.java:322) - Timeout while trying to close connection on ... - force closing - server will close session on shutdown or expiration.
java.util.concurrent.TimeoutException
at java.util.concurrent.CompletableFuture.timedGet(CompletableFuture.java:1771)
Is there any suggestion?
This might be a connectivity problem with the server which you are not able to observe while sending the query because you are not waiting for the future to complete.
When you do a client.submit("query...");, you receive a future. You need to wait for that future to complete to observe any exceptions (or success).
I would suggest the following:
Try hitting the server with a health status call using curl to verify connectivity with the server.
Replace the client.submit("query..."); with client.submit("query...").all().join(); to get the error during connection with the server.
I'm implementing a Thrift client in order to make connection to a built-in scribe server.
Everything is going OK if I use a standard Log method, like this:
public boolean log(List<LogEntry> messages) {
boolean ret = false;
PooledClient client = borrowClient();
try {
if ((client != null) && (client.getClient() != null)) {
ResultCode result = client.getClient().Log(messages);
ret = (result != null && result.equals(ResultCode.OK));
returnClient(client);
}
} catch (Exception ex) {
logger.error(LogUtil.stackTrace(ex));
invalidClient(client);
}
return ret;
}
However, when I use send_Log instead:
public void send_Log(List<LogEntry> messages) {
PooledClient client = borrowClient();
try {
if ((client != null) && (client.getClient() != null)) {
client.getClient().send_Log(messages);
returnClient(client);
}
} catch (Exception ex) {
logger.error(LogUtil.stackTrace(ex));
invalidClient(client);
}
}
It acctually causes some problems:
Total network connection to port 1463 (default port for a scribe server) is going to increase so much, and always in a CLOSE_WAIT state.
Cause my application got stuck without throwing any error, I think it may be an issue with network connection.
what if send without recv
As this is clearly TCP, the sender will block (in blocking mode), or incur EAGAIN/EWOULDBLOCK in non-blocking mode. EDIT It is now clear that you want to send without receiving the reply. You can do that by just sending and then closing the socket, but that may cause the peer to incur ECONNRESET, which may upset it. You should really implement the application protocol correctly.
1/ Total network connection to port 1463 (default port for a scribe server) is going to increase so much, and always in a CLOSE_WAIT state.
Lots of ports in CLOSE_WAIT state indicates a socket leak on the part of the local application.
2/ Cause my application got stuck without throwing any error. I think it may be an issues with network connection.
It is an issue with sending and not receiving.
Since you labelled this as a Thrift related question, the answer is oneway.
service foo {
oneway void FireAndForget(1: some args)
}
The oneway keyword does exactly what the name suggests. You get a client implementation that only sends and does not wait for anything to be returned from the server. This rule also includes exceptions. Hence a oneway method must always be void and can't throw any exceptions.
However, when I use send_Log instead ...
client.getClient().send_Log(messages);
Neither one of the Thrift-generated send_Xxx and recv_Xxx methods are meant to be public. That's why they are usually either private or protected methods. They should not be called directly, unless you are sure that you know what you are doing (and very obviously the latter is not the case here).
And since the real question is about performance: Why don't you just delegate the call(s) into a secondary thread? That way the I/O will not block the UI.
This HttpHandler does not send a response if con.Open() throws an exception, for example if faultyConnectionString has an invalid database name. Why?
public void ProcessRequest(HttpContext context)
{
int status = 400;
string message = "Test error!";
string faultyConnectionString = "Data Source=LOCALHOST\\SQLEXPRESS;Initial Catalog=XXX;User ID=XXX;Password=XXX";
try
{
using (SqlConnection con = new SqlConnection(faultyConnectionString))
{
//throw new Exception("This works as expected, and is returned to client");
con.Open();
}
}
catch (Exception ex)
{
status = 500;
message = "Test Exception: " + ex.Message;
}
context.Response.StatusCode = status;
context.Response.StatusDescription = message;
}
Here is how I am handling the call in the client:
function GetContacts() {
$.ajax({
type: "POST",
url: "xxx.ashx",
data: "",
contentType: "application/x-www-form-urlencoded; charset=utf-8",
dataType: "text", // "json",
success: function (response, a, b) {
alert(response.status + " " + response.statusText);
},
error: function (response, a, b) {
alert(response.status + " " + response.statusText);
}
});
}
If I F12 in FireFox it shows me that there is no Response received after the request is sent. In IE it shows me "SCRIPT7002: XMLHttpRequest: Network Error 0x2ef3, Could not complete the operation due to error 00002ef3.". In both cases the jquery ajax call returns status=0 and statusText="error".
If I comment out the two lines inside the catch block then it works as expected, sending the 403 code to the client and ignoring the exception.
Different types of exceptions do not have the same problem. If I throw a new Exception() before con.Open() then it also works as expected. What is different with SqlException?
UPDATE: The very first time I hit ProcessRequest it gets called 5 times in succession before the client shows the status=0 result (breakpoint on first line is hit 5 times).
FIDDLER: If I fire up Fiddler it (fiddler) intercepts the transaction and sends "504 Fiddler - Receive Failure" to my ajax call. Looks like the initial repetition may be a retry mechanism, when fiddler is active it does it 13 times.
Fiddler reports: "Session #xxx raised exception System.Net.Sockets.SocketException An existing connection was forcibly closed by the remote host".
I believe the way your client (browser) handles 404 errors is what is causing this, and each browser type is handling the error differently. 404 errors are specific to "Not Found" so you may want to use a different error code such as a 500 error. More info on error codes is available here: http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html
Please keep in mind that passing back detailed error messages to a client could be a security issue due to information leakage. You may be better off passing back a generic error to the client and logging detailed error information on the server side.
Edit:
Testing this locally, the way you are setting context.Response.StatusDescription to contain ex.Message is producing an invalid HTTP response. Try only placing text such as Internal Server Error in there. Additional details can be added to the body of the response using context.Response.Write(bodyText) but please keep the security implications of this in mind.
When I run the following code without a network connection, I get a bad access error on the last line.
Poco::URI uri(sRemoteLoggingURL);
HTTPClientSession session(uri.getHost(), uri.getPort());
HTTPRequest request(HTTPRequest::HTTP_POST, uri.getPathAndQuery());
request.set("User-Agent", "Poco");
string reqBody = "{\"logMessage\":\""+ message + "\", \"application_name\":\""+ sAppName +"\"}";
request.setContentLength( reqBody.length() );
std::ostream& sessionStream = session.sendRequest(request);
Is this expected behavior? Do I need to check for network connectivity before I try to send a request? If so, how do I do that? I've tried session.connected(), but that is returning false even when I do have a network connection.
I think I figured it out. Apparently, you need to be sure to call reset on the session before you destroy it (or before it goes out of scope) if there's an exception. This code works:
Poco::URI uri(sRemoteLoggingURL);
HTTPClientSession session(uri.getHost(), uri.getPort());
try{
HTTPRequest request(HTTPRequest::HTTP_POST, uri.getPathAndQuery());
request.set("User-Agent", "Poco");
string reqBody = "{\"logMessage\":\""+ message + "\", \"application_name\":\""+ sAppName +"\"}";
request.setContentLength( reqBody.length() );
std::ostream& sessionStream = session.sendRequest(request);
if (sessionStream.good()) {
sessionStream << reqBody;
HTTPResponse res;
string text;
istream &is = session.receiveResponse(res);
StreamCopier::copyToString(is, text);
}
}catch(Poco::Exception& e){
// apparently, you MUST call reset before destroying the session, or you'll crash
session.reset();
sdfLog::logFormat("appContent::doIdle Poco::Exception: %s\n", e.what());
}catch(...){
session.reset();
sdfLog::logFormat("appContent::doIdle exception in remote logger %s\n");
}
I'm trying to improve the information provided in response to an error handled within an app.
This is the code:
Try
httpRequestObj = HttpWebRequest.Create(strRequest)
httpRequestObj.Method = "GET"
httpRequestObj.UseDefaultCredentials = True
* httpResponse = httpRequestObj.GetResponse
Using reader As StreamReader = New StreamReader(httpResponse.GetResponseStream())
strXML = reader.ReadToEnd()
End Using
Catch ex As WebException
'do something with ex
End Try
The webexception is thrown on the * line
Currently all I see in the Exception is "The remote server returned an error: (500) Internal Server Error". I've looked at the exception in debug but the info I need isn't there- I guess the response would need to be read in to see that info but it never gets that far.
If I take the request and paste it into my browser directly I can see the error details in XML format that is returned from the API I'm calling, info like:
<Error>
<description>info I want to get to here</description>
<detail />
<code>info I want to get to here</code>
<source />
<category>info I want to get to here</category>
<file>info I want to get to here</file>
<line>info I want to get to here</line>
<pad />
</Error>
Is there any way I can change this code so that I can get past the 500 error and see the actual response, I'd like to be able to parse this xml to find out the real problem for the failure.
Note: the Exception does have an ex.Response (System.Net.HttpWebResponse), but I can't see the info I need in there, only a load of Header info.
You can get the error response from the exception....
try
{
....
} catch(Exception e) {
if (e is WebException && ((WebException)e).Status==WebExceptionStatus.ProtocolError)
{
WebResponse errResp = ((WebException)e).Response;
using(Stream respStream = errResp.GetResponseStream())
{
// read the error response
}
}
}
System.Net.WebResponse response = null;
try
{
response = wreq.GetResponse();
}
catch (WebException e)
{
if (e.Status == WebExceptionStatus.ProtocolError)
{
string error = new System.IO.StreamReader(e.Response.GetResponseStream()).ReadToEnd();
}
}
catch (Exception e)
{
}
as simple as this, You will get entire response in the string error.
Try to use Fiddler. It's debuging proxy, which will show you all data sending between client and server. You'll be able to see all headers and context as well.