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HTTP Connection

Shared Configuration

The HTTP Connection resource describes the characteristics of the connection used to receive incoming HTTP requests. This resource is used when TIBCO ActiveMatrix BusinessWorks expects to receive an HTTP request on a specific port where a process engine is running. For example, the process starters HTTP Receiver and SOAP Event Source and the signal-in activity Wait for HTTP Request receive HTTP requests.

There can be at most one process with an HTTP Receiver or Wait for HTTP Request that uses the same HTTP Connection resource. This restriction allows the HTTP server listening for incoming requests to dispatch the request to the correct process. There can be more than one SOAP Event Source that uses the same HTTP Connection. Also, SOAP Event Source and HTTP activities can use the same HTTP Connection resource and the HTTP server correctly dispatches the incoming request to the correct process.

Two types of servers are available for the HTTP Connection resource: Tomcat and HTTPComponent.

Tomcat has a synchronous request response paradigm and can be used in scenarios where high throughput is important. To achieve a good throughput with Tomcat, the maxprocessor value should be almost equal to the number of concurrent requests the server can handle. Note that increasing the maxprocessor count also increases the memory footprint.

HTTPComponent is a light-weight and scalable server based on NIO which can be useful in scenarios where handling thousands of requests in a resource efficient manner is more important than the throughput. HTTPComponent server gives a consistent throughput for any number of concurrent requests with little or no increase in its worker thread (maxprocessor thread).

You can choose the server type at runtime by setting the global property bw.plugin.http.server.serverType in the file bwengine.tra. Using this property, you can use the HTTPComponent server at run-time for older projects without having to modify the server type at design-time. The value set for this property in the bwengine.tra file overrides the value that is set in design-time.

The HTTP Connection resource can specify that the HTTPS (secure sockets layer or SSL) protocol must be used by clients. If this is enabled, you can configure the SSL parameters for the HTTP server using the Configure SSL Button. See Configure SSL Button for more information.

If you have multiple HTTP Connection resources specified by multiple HTTP Receiver process starters, the HTTP servers require that all of the connections must be valid to initialize all HTTP Receivers. Therefore, make certain that all HTTP Connection resources have valid configurations before testing or deploying the project.

Configuration

The Configuration tab has the following fields.

Field	Global Var?	Description
Name	No	The name to appear as the label for the resource.
Description	No	Short description of the shared resource.
Host	Yes	Specifies the name of the host that accepts the incoming requests. For machines that have only one network card, the default value localhost specifies the current machine. For machines that have more than one network card, this field specifies the host name of the card that will be used to accept incoming HTTP requests. If there is more than one network card on the machine, and you specify localhost in this field, all network cards on the machine will listen for incoming HTTP requests on the specified port. Note: Only one HTTP server can be started on each port. Therefore, if you have a machine with multiple network cards, make certain that all HTTP Connection resources that use the same host name specify different port numbers. Note: When the hostname is localhost, TIBCO ActiveMatrix BusinessWorks considers the machine as a non multi home environment. Hence it is not required to set the bw.plugin.http.server.defaultHost property in bwengine.tra file. However, when the hostname is anything other than the localhost, then TIBCO Activematrix BusinessWorks considers the machine as a multi home environment. Set the bw.plugin.http.server.defaultHost property in bwengine.tra file to the same value as has been set in the host field of HTTP Shared Connection for default host.
Port	Yes	Port number on which to listen for incoming HTTP requests.
SSL	No	Specifies whether incoming requests must use the HTTPS (secure socket layer or SSL) protocol. This protocol authenticates the server to the client, and optionally authenticates the client to the server. Enabling this field allows you to specify SSL parameters with the Configure SSL button (see Configure SSL Button).
Server Type	No	Specifies the server type to be used. The drop-down lists the available options: Tomcat and HTTPComponent.

Configure SSL Button

The Configure SSL button allows you to specify the SSL parameters for the HTTP connection. The following are the fields in the SSL Configuration for HTTPS Connections dialog:

The HTTPComponent server type does not support Entrust based SSL. Set property java.property.TIBCO_SECURITY_VENDOR to j2se in the bwengine.tra file for HTTP SSL to work with HTTPComponent server type.

Field	Description
Requires Client Authentication	Checking this field requires clients to present their digital certificate before connecting to the HTTP server. When this field is checked, the Trusted Certificates Folder becomes enabled so that you can specify a location containing the list of trusted certificate authorities.
Trusted Certificates Folder	This field is only applicable when the Requires Client Authentication field is checked. This field specifies a folder in the project containing one or more certificates from trusted certificate authorities. This folder is checked when a client connects to ensure that the client is trusted. This prevents connections from rogue clients.
Identity	This is an Identity resource that contains the HTTP server’s digital certificate and private key. See TIBCO Designer Palette Reference for more information.
Strong Cipher Suites Only	When checked, this field specifies that the minimum strength of the cipher suites used can be specified with the bw.plugin.security.strongcipher.minstrength custom engine property. See TIBCO ActiveMatrix BusinessWorks Administration for more information about this property. The default value of the property disables cipher suites with an effective key length below 128 bits. When this field is unchecked, only cipher suites with an effective key length of up to 128 bits can be used.

Advanced

The Advanced tab has the following fields

Field	Global Var?	Description
Enable DNS Lookups	No	Checking this field enables a Domain Name System (DNS) lookup for HTTP clients so that the IP address is resolved to a DNS name. This can adversely affect throughput. Uncheck this field by default and check this field only when required.
Connection Properties
maxPostSize	Yes	This property is available when the Server Type Tomcat is selected. Specifies the maximum size in bytes of the POST that the container FORM URL parameter parsing can handle. By default, the value of this field is set to 2M or 2097152 bytes. Setting the value less than or equal to zero disables the limit for maxPostSize.
maxSavePostSize	Yes	This property is available when the Server Type Tomcat is selected. Specifies the maximum size in bytes of the POST that the container can save/buffer during FORM or CLIENT-CERT authentication. During FORM authentication, the request message is saved while the user is redirected to the login page. It is retained until the user authentication succeeds or the session associated with the authentication request expires. During CLIENT-CERT authentication, the request message is buffered for the entire duration of the SSL handshake. Once the request is processed, the buffer is emptied. However, in both the cases the buffering happens before the user is authenticated. By default, the value of this field is set to 4K or 4096 bytes. Setting the value to -1 disables the limit for this field.
URI Encoding	Yes	Specifies the character encoding used to decode the URI bytes. If you do not set any value for uriEncoding, the default encoding set in HTTP Receiver is used. Specifying this property automatically sets the Tomcat property useBodyEncodingForURI to false.
acceptCount	Yes	This property is available when the Server Type Tomcat is selected. Specifies the maximum number of incoming connection requests that can be accepted when all HTTP processors are in use. The default value for acceptCount is 100. Incoming requests received after the acceptCount limit is reached are rejected. If the value is not set in TIBCO Designer, you can set the value for either design-time or run-time. • Specify the value in a .config file. Provide the file name and location while starting TIBCO Designer to set the value of acceptCount in design-time. • Specify the value in bwengine.tra to set the value in run-time.
compressableMimeType	Yes	Specifies the list of MIME types for which HTTP compression may be used. The default value for this comma separated list is text/html, text/xml, text/plain.
compression	Yes	Specifies if the output of the HTTP Connection is compressed using HTTP/1.1 GZIP compression. The acceptable values for this field are - off: By default, the compression is disabled. on: Allows compression for text data. force: Forces compression in all cases. Note that if the content length is not known and compression is enabled, the output will still be compressed. any numerical integer value: Any numerical value equivalent to "on", and specifies the minimum amount of data before the output can be compressed.
connectionTimeOut	Yes	Specifies the number of milliseconds that the Connector waits for the request URI line to be presented after the connection is accepted. The default value is 60000 i.e., 60 seconds.

Custom Properties for the HTTP Palette

In some situations, you may want to alter the configuration of the HTTP server that receives incoming HTTP requests for TIBCO ActiveMatrix BusinessWorks. You can configure the following custom properties:

•	bw.plugin.http.server.minProcessors : the minimum number of threads available for incoming HTTP requests. The HTTP server creates the number of threads specified by this paramter when it starts up. The default value of this property is 10.

•	bw.plugin.http.server.maxProcessors : the maximum number of threads available for incoming HTTP requests. The HTTP server will not create more than the number of threads specified by this parameter. The default value of this property is 75.

•	bw.plugin.http.server.maxSpareProcessors : the maximum number of unused request processing threads that can exist until the thread pool starts stopping the unnecessary threads. The default maximum number of spare threads is 50.

•

bw.plugin.http.server.acceptCount : the maximum queue size for incoming requests. Incoming requests that are not handled by available threads are placed on the queue until they can be processed. If the queue is full, new incoming requests are refused with an error. The default value of this property is 100.

•

bw.plugin.http.server.restrictIPAddresses : a comma-separated list of regular expression patterns that is compared with the remote client’s IP address before accepting or rejecting requests from the client. The remote IP address of the client must not match for any request from this client to be accepted.

If the same IP address is allowed and restricted, the restriction overrides the allowance and the IP address will be restricted.

•	bw.plugin.http.server.serverType : the type of server to be used for the HTTP connection resource. Two server types are available: Tomcat and HTTP Component. The default value of this property is Tomcat.

•	bw.plugin.http.server.httpcomponents.workerThread : the maximum number of web server threads available to handle HTTP requests for the HTTPComponents server type. The default value of this property is 50.

•

bw.plugin.http.server.restrictHttpMethods : specific HTTP methods can be disabled. By default, none of the HTTP methods are restricted by the server. You can specify a comma-separated list of methods that are to be restricted. These restrictions are then applicable to all resources accessed on this server, for all roles. You cannot disable methods selectively for a particular service or for a particular server.

If you have a large number of incoming requests, you may want to change the values of these properties to handle more incoming requests concurrently.

See TIBCO ActiveMatrix BusinessWorks Administration for more information about setting custom engine properties.

When a client sends a request that cannot be processed because no threads are available, TIBCO ActiveMatrix BusinessWorks returns a ConnectionRefused exception to the client. The HTTP Receiver uses the minProcessors/maxProcessors properties to control the flow of incoming HTTP requests. If you set the Flow Limit deployment property for a process definition with the HTTP Receiver process starter, maxProcessors is set to <flowLimitValue> - 1 and minProcessors is set to <maxProcessorValue>/2. Therefore, the Flow Limit value will never be reached because the maxProcessors property will prevent new requests from being accepted before the Flow Limit value is reached.

Copyright © Cloud Software Group, Inc. All Rights Reserved