Sandbox Directives

LimitClients

Description	Set the number of simultaneous clients
Synopsis	LimitClient count
Context	Default Server
Example	LimitClient 10

The LimitClient directive defines the maximum number of simultaneous client connections that can be supported. Client connection requests in excess of this count will be rejected. A limit of 0 means unlimited.

NOTE that many browsers can and will initiate multiple connections when requesting a page.

LimitRequestBody

Description	Set the maximum size of the request body from the client.
Synopsis	LimitRequestBody limit
Context	Default Server
Example	LimitRequestBody 65536

The LimitRequestBody directive defines a maximum size for the request body. For embedded applications, it is useful to limit the maximum request body to the expected maximum. This ensures that rogue or malicious requests will not cause the server to allocate unwanted memory to servicing the request.

The limit is an integer between zero and 2147483647 (2GB), where zero means unlimited. If a request is received that is larger than the limit, it will be rejected and the client will receive an error. The default limit is 64 MB.

SECURITY NOTE: This directive can be quite useful in certain denial-of-service attacks where the attacker sends large documents of a certain type.

LimitRequestFields

Description	Maximum number of header lines in the request body from the client.
Synopsis	LimitRequestFields limit
Context	Default Server
Example	LimitRequestFields 64

The LimitRequestFields directive defines a maximum number of header lines that may be in a request from a client. For embedded applications, it is useful to limit the number of header lines to the expected maximum. This ensures that rogue or malicious requests will not cause the server to allocate unwanted memory to servicing the request. Typically, HTTP requests will not have more than 15-20 header lines.

The limit is an integer between zero and 4096, where zero means unlimited. If a request is received that has more header lines than the limit, it will be rejected and the client will receive an error. The default limit is 40.

SECURITY NOTE: This directive can be quite useful in certain denial-of-service attacks where the attacker sends requests with many spurious header lines.

LimitRequestFieldSize

Description	Maximum size of the request headers from the client
Synopsis	LimitRequestFieldSize limit
Context	Default Server
Example	LimitRequestFieldSize 65536

The LimitRequestFieldSize directive defines the maximum size of the request header from the client. For embedded applications, it is useful to limit the size of the header to the expected maximum. This ensures that rogue or malicious requests will not cause the server to allocate unwanted memory to servicing the request. Typically, HTTP requests will not have more than 4K of header data.

The limit is an integer between zero and 1 MB, where zero means unlimited. If a request is received that has a header larger than the limit, it will be rejected and the client will receive an error. The default limit is 8 K.

SECURITY NOTE: This directive can be quite useful in certain denial-of-service attacks where the attacker sends requests with large bogus headers.

LimitRequestLine

Description	Maximum size of the request first line from the client
Synopsis	LimitRequestLine limit
Context	Default Server
Example	LimitRequestLine 65536

The LimitRequestLine directive defines a maximum size of the first line of the request from a client. For embedded applications, it is useful to limit the size of the first line of the requestto the expected maximum. This ensures that rogue or malicious requests will not cause the server to allocate unwanted memory to servicing the request.

The limit is an integer between zero and 256 K where zero means unlimited. If a request is received that has a first line larger than the limit, it will be rejected and the client will receive an error. The default limit is 4 K.

SECURITY NOTE: This directive can be quite useful in certain denial-of-service attacks where the attacker sends requests with large bogus request headers.

LimitResponseBody

Description	Set the maximum size of the response body buffered by a dynamic Appweb handler.
Synopsis	LimitResponseBody number
Context	Default Server
Example	LimitResponseBody 65536

The LimitResponseBody directive defines the maximum size for data generated by an Appweb handler that uses unchunked buffered output. Appweb handlers that generate dynamic output typically buffer output for performance. This directive places a limit on the amount of memory consumed by such buffering handlers.

NOTE: this does not imply a maximum response size. It merely limits the memory consumed when trying to buffer the data. Appweb handlers will flush the buffer and use HTTP/1.1 chunked output if the amount of response data exceeds the output buffer size..

The limit is an integer between zero and 4 MB, where zero means unlimited. These limits can be increased by recompiling Appweb using the source code. The default limit is 64K or 8K in squeeze mode.

NOTE: this is a proprietary directive of Appweb and is not supported by Apache.

LimitScriptSize

Description	Set the maximum size of the response body buffered by a dynamic Appweb handler.
Synopsis	LimitResponseBody number
Context	Default Server
Example	LimitResponseBody 65536

The LimitResponseBody directive defines the maximum size for data generated by an Appweb handler that uses unchunked buffered output. Appweb handlers that generate dynamic output typically buffer output for performance. This directive places a limit on the amount of memory consumed by such buffering handlers.

NOTE: this does not imply a maximum response size. It merely limits the memory consumed when trying to buffer the data. Appweb handlers will flush the buffer and use HTTP/1.1 chunked output if the amount of response data exceeds the output buffer size..

The limit is an integer between zero and 4 MB, where zero means unlimited. These limits can be increased by recompiling Appweb using the source code. The default limit is 64K or 8K in squeeze mode.

NOTE: this is a proprietary directive of Appweb and is not supported by Apache.

LimitUrl

Description	Maximum size of a URL in a request from a client.
Synopsis	LimitUrl limit
Context	Default Server
Example	LimitUrl 4096

The LimitUrl directive defines the maximum size of a URL in Appweb. IFor embedded applications, it is useful to limit the number of header lines to the expected maximum. This ensures that rogue or malicious requests will not cause the server to allocate unwanted memory to servicing the request.

The limit is an integer between zero and 256 K where zero means unlimited. If a request is received that has a URL larger than the limit, it will be rejected and the client will receive an error. The default limit is 4 K.

SECURITY NOTE: This directive can be quite useful in certain denial-of-service attacks where the attacker sends requests with bogus URLs.

NOTE: this is a proprietary directive of Appweb and is not supported by Apache.

StartThreads

Description	Number of threads to preallocate in the Appweb thread pool
Synopsis	StartThreads number
Context	Default Server
Example	StartThreads 100

The StartThreads directive will preallocate the specified number of threads on startup and then ensure that the thread pool always has at least this number of threads.

Appweb will automatically adjust the number of pool thread between the minimum specified by this directive and the maximum specified by the ThreadLimit directive or via the Appweb command line. Appweb will prune idle threads to reduce resource consumption as required.

ThreadLimit

Description	Maximum number of threads to allocate for the Appweb thread pool.
Synopsis	ThreadLimit number
Context	Default Server
Example	ThreadLimit 8

The ThreadLimit directive defines a maximum number of threads for the Appweb thread pool. When running in multithreaded mode, Appweb will use a pool thread to service each request and then will return the thread to the pool. This results in a highly responsive and scalable architecture with excellent throughput characteristics. Each thread requires a thread stack and thus consumes memory. By limiting the number of threads, memory can be conserved.

If the maximum number of threads is also specified via the Appweb command line, the command line value will take precedence.

Appweb will automatically adjust the number of pool thread between the minimum specified by the StartThreads directive and the maximum specified by this directive. Appweb will prune idle threads to reduce resource consumption as required.

ThreadStackSize

Description	Define the size of the stack to allocate for each thread
Synopsis	ThreadStackSize limit
Context	Default Server
Example	ThreadStackSize 65536

The ThreadStackSize directive defines the size of the thread stack to allocate for each thread.

The limit is an integer between zero and an operating system defined maximum  where zero means use the system default. The default limit is 0 which implies the system default.

If you are experiencing crashes when running multi-threaded and Appweb runs without error when running single-threaded, you may need to increase this value. See the Appweb command line for details on running single user by setting the "-p 0" option.