core_http_client.h File Reference

User facing functions of the HTTP Client library. More...

#include <stdint.h>
#include <stddef.h>
#include "core_http_config.h"
#include "core_http_config_defaults.h"
#include "transport_interface.h"

Go to the source code of this file.

Data Structures
struct	HTTPRequestHeaders_t
	Represents header data that will be sent in an HTTP request. More...
struct	HTTPRequestInfo_t
	Configurations of the initial request headers. More...
struct	HTTPClient_ResponseHeaderParsingCallback_t
	Callback to intercept headers during the first parse through of the response as it is received from the network. More...
struct	HTTPResponse_t
	Represents an HTTP response. More...

Macros
#define	HTTP_METHOD_GET   "GET"
#define	HTTP_METHOD_PUT   "PUT"
#define	HTTP_METHOD_POST   "POST"
#define	HTTP_METHOD_HEAD   "HEAD"
#define	HTTP_MAX_CONTENT_LENGTH_HEADER_LENGTH   sizeof( "Content-Length: 4294967295" ) - 1U
	The maximum Content-Length header field and value that could be written to the request header buffer.
#define	HTTP_SEND_DISABLE_CONTENT_LENGTH_FLAG   0x1U
	Set this flag to disable automatically writing the Content-Length header to send to the server. More...
#define	HTTP_REQUEST_KEEP_ALIVE_FLAG   0x1U
	Set this flag to indicate that the request is for a persistent connection. More...
#define	HTTP_RESPONSE_CONNECTION_CLOSE_FLAG   0x1U
	This will be set to true if header "Connection: close" is found. More...
#define	HTTP_RESPONSE_CONNECTION_KEEP_ALIVE_FLAG   0x2U
	This will be set to true if header "Connection: Keep-Alive" is found. More...
#define	HTTP_RANGE_REQUEST_END_OF_FILE   -1
	Flag that represents End of File byte in the range specification of a Range Request. This flag should be used ONLY for 2 kinds of range specifications when creating the Range Request header through the HTTPClient_AddRangeHeader function: More...

Typedefs
typedef uint32_t(*	HTTPClient_GetCurrentTimeFunc_t) (void)
	Application provided function to query the current time in milliseconds. More...

Enumerations
enum	HTTPStatus_t {   HTTPSuccess, HTTPInvalidParameter, HTTPNetworkError, HTTPPartialResponse,   HTTPNoResponse, HTTPInsufficientMemory, HTTPSecurityAlertResponseHeadersSizeLimitExceeded, HTTPSecurityAlertExtraneousResponseData,   HTTPSecurityAlertInvalidChunkHeader, HTTPSecurityAlertInvalidProtocolVersion, HTTPSecurityAlertInvalidStatusCode, HTTPSecurityAlertInvalidCharacter,   HTTPSecurityAlertInvalidContentLength, HTTPParserInternalError, HTTPHeaderNotFound, HTTPInvalidResponse }
	The HTTP Client library return status. More...

Functions
HTTPStatus_t	HTTPClient_InitializeRequestHeaders (HTTPRequestHeaders_t *pRequestHeaders, const HTTPRequestInfo_t *pRequestInfo)
	Initialize the request headers, stored in HTTPRequestHeaders_t.pBuffer, with initial configurations from HTTPRequestInfo_t. This method is expected to be called before sending a new request. More...
HTTPStatus_t	HTTPClient_AddHeader (HTTPRequestHeaders_t *pRequestHeaders, const char *pField, size_t fieldLen, const char *pValue, size_t valueLen)
	Add a header to the request headers stored in HTTPRequestHeaders_t.pBuffer. More...
HTTPStatus_t	HTTPClient_AddRangeHeader (HTTPRequestHeaders_t *pRequestHeaders, int32_t rangeStartOrlastNbytes, int32_t rangeEnd)
	Add the byte range request header to the request headers store in HTTPRequestHeaders_t.pBuffer. More...
HTTPStatus_t	HTTPClient_Send (const TransportInterface_t *pTransport, HTTPRequestHeaders_t *pRequestHeaders, const uint8_t *pRequestBodyBuf, size_t reqBodyBufLen, HTTPResponse_t *pResponse, uint32_t sendFlags)
	Send the request headers in HTTPRequestHeaders_t.pBuffer and request body in pRequestBodyBuf over the transport. The response is received in HTTPResponse_t.pBuffer. More...
HTTPStatus_t	HTTPClient_ReadHeader (const HTTPResponse_t *pResponse, const char *pField, size_t fieldLen, const char **pValueLoc, size_t *pValueLen)
	Read a header from a buffer containing a complete HTTP response. This will return the location of the response header value in the HTTPResponse_t.pBuffer buffer. More...
const char *	HTTPClient_strerror (HTTPStatus_t status)
	Error code to string conversion utility for HTTP Client library. More...

Detailed Description

User facing functions of the HTTP Client library.

Function Documentation

HTTPClient_InitializeRequestHeaders()

HTTPStatus_t HTTPClient_InitializeRequestHeaders	(	HTTPRequestHeaders_t *	pRequestHeaders,
		const HTTPRequestInfo_t *	pRequestInfo
	)

Initialize the request headers, stored in HTTPRequestHeaders_t.pBuffer, with initial configurations from HTTPRequestInfo_t. This method is expected to be called before sending a new request.

Upon return, HTTPRequestHeaders_t.headersLen will be updated with the number of bytes written.

Each line in the header is listed below and written in this order: <HTTPRequestInfo_t.pMethod> <HTTPRequestInfo_t.pPath> <HTTP_PROTOCOL_VERSION> User-Agent: <HTTP_USER_AGENT_VALUE> Host: <HTTPRequestInfo_t.pHost>

Note that "Connection" header can be added and set to "keep-alive" by activating the HTTP_REQUEST_KEEP_ALIVE_FLAG in HTTPRequestInfo_t.reqFlags.

Parameters

[in]	pRequestHeaders	Request header buffer information.
[in]	pRequestInfo	Initial request header configurations.

Returns

One of the following:

• HTTPSuccess (If successful)
• HTTPInvalidParameter (If any provided parameters or their members are invalid.)
• HTTPInsufficientMemory (If provided buffer size is not large enough to hold headers.)

Example

HTTPStatus_t httpLibraryStatus = HTTPSuccess;
// Declare an HTTPRequestHeaders_t and HTTPRequestInfo_t.
HTTPRequestHeaders_t requestHeaders = { 0 };
HTTPRequestInfo_t requestInfo = { 0 };
// A buffer that will fit the Request-Line, the User-Agent header line, and
// the Host header line.
uint8_t requestHeaderBuffer[ 256 ] = { 0 };
 
// Set a buffer to serialize request headers to.
requestHeaders.pBuffer = requestHeaderBuffer;
requestHeaders.bufferLen = 256;
 
// Set the Method, Path, and Host in the HTTPRequestInfo_t.
requestInfo.pMethod = HTTP_METHOD_GET;
requestInfo.methodLen = sizeof( HTTP_METHOD_GET ) - 1U;
requestInfo.pPath = "/html/rfc2616"
requestInfo.pathLen = sizeof( "/html/rfc2616" ) - 1U;
requestInfo.pHost = "tools.ietf.org"
requestInfo.hostLen = sizeof( "tools.ietf.org" ) - 1U;
requestInfo.reqFlags |= HTTP_REQUEST_KEEP_ALIVE_FLAG;
 
httpLibraryStatus = HTTPClient_InitializeRequestHeaders( &requestHeaders,
                                                         &requestInfo );

HTTPClient_AddHeader()

HTTPStatus_t HTTPClient_AddHeader	(	HTTPRequestHeaders_t *	pRequestHeaders,
		const char *	pField,
		size_t	fieldLen,
		const char *	pValue,
		size_t	valueLen
	)

Add a header to the request headers stored in HTTPRequestHeaders_t.pBuffer.

Upon return, pRequestHeaders->headersLen will be updated with the number of bytes written.

Headers are written in the following format:

<field>: <value>\r\n\r\n

The trailing \r\n that denotes the end of the header lines is overwritten, if it already exists in the buffer.

Note

This function validates only that \r, \n, and : are not present in pValue or pField. : is allowed in pValue.

Parameters

[in]	pRequestHeaders	Request header buffer information.
[in]	pField	The header field name to write. The data should be ISO 8859-1 (Latin-1) encoded per the HTTP standard, but the API does not perform the character set validation.
[in]	fieldLen	The byte length of the header field name.
[in]	pValue	The header value to write. The data should be ISO 8859-1 (Latin-1) encoded per the HTTP standard, but the API does not perform the character set validation.
[in]	valueLen	The byte length of the header field value.

Returns

One of the following:

• HTTPSuccess (If successful.)
• HTTPInvalidParameter (If any provided parameters or their members are invalid.)
• HTTPInsufficientMemory (If application-provided buffer is not large enough to hold headers.)
• HTTPSecurityAlertInvalidCharacter (If an invalid character was found in pField or pValue.)

Example

HTTPStatus_t httpLibraryStatus = HTTPSuccess;
// Assume that requestHeaders has already been initialized with
// HTTPClient_InitializeRequestHeaders().
HTTPRequestHeaders_t requestHeaders;
 
httpLibraryStatus = HTTPClient_AddHeader( &requestHeaders,
                                          "Request-Header-Field",
                                          sizeof( "Request-Header-Field" ) - 1U,
                                          "Request-Header-Value",
                                          sizeof("Request-Header-Value") - 1U );

HTTPClient_AddRangeHeader()

HTTPStatus_t HTTPClient_AddRangeHeader	(	HTTPRequestHeaders_t *	pRequestHeaders,
		int32_t	rangeStartOrlastNbytes,
		int32_t	rangeEnd
	)

Add the byte range request header to the request headers store in HTTPRequestHeaders_t.pBuffer.

For example, if requesting for the first 1kB of a file the following would be written: Range: bytes=0-1023\r\n\r\n.

The trailing \r\n that denotes the end of the header lines is overwritten, if it already exists in the buffer.

There are 3 different forms of range specification, determined by the combination of rangeStartOrLastNBytes and rangeEnd parameter values:

1. Request containing both parameters for the byte range [rangeStart, rangeEnd] where rangeStartOrLastNBytes <= rangeEnd. Example request header line: Range: bytes=0-1023\r\n for requesting bytes in the range [0, 1023].
   Example

   HTTPStatus_t httpLibraryStatus = HTTPSuccess;
   // Assume that requestHeaders has already been initialized with
   // HTTPClient_InitializeRequestHeaders().
   HTTPRequestHeaders_t requestHeaders;
    
   // Request for bytes 0 to 1023.
   httpLibraryStatus = HTTPClient_AddRangeHeader( &requestHeaders, 0, 1023 );

2. Request for the last N bytes, represented by rangeStartOrlastNbytes. rangeStartOrlastNbytes should be negative and rangeEnd should be HTTP_RANGE_REQUEST_END_OF_FILE. Example request header line: Range: bytes=-512\r\n for requesting the last 512 bytes (or bytes in the range [512, 1023] for a 1KB sized file).
   Example

   HTTPStatus_t httpLibraryStatus = HTTPSuccess;
   // Assume that requestHeaders has already been initialized with
   // HTTPClient_InitializeRequestHeaders().
   HTTPRequestHeaders_t requestHeaders;
    
   // Request for the last 512 bytes.
   httpLibraryStatus = HTTPClient_AddRangeHeader( &requestHeaders, -512, HTTP_RANGE_REQUEST_END_OF_FILE)

3. Request for all bytes (till the end of byte sequence) from byte N, represented by rangeStartOrlastNbytes. rangeStartOrlastNbytes should be >= 0 and rangeEnd should be HTTP_RANGE_REQUEST_END_OF_FILE.
   Example request header line: Range: bytes=256-\r\n for requesting all bytes after and including byte 256 (or bytes in the range [256,1023] for a 1kB sized file).
   Example

   HTTPStatus_t httpLibraryStatus = HTTPSuccess;
   // Assume that requestHeaders has already been initialized with
   // HTTPClient_InitializeRequestHeaders().
   HTTPRequestHeaders_t requestHeaders;
    
   // Request for all bytes from byte 256 onward.
   httpLibraryStatus = HTTPClient_AddRangeHeader( &requestHeaders, 256, HTTP_RANGE_REQUEST_END_OF_FILE)

Parameters

[in]	pRequestHeaders	Request header buffer information.
[in]	rangeStartOrlastNbytes	Represents either the starting byte for a range OR the last N number of bytes in the requested file.
[in]	rangeEnd	The ending range for the requested file. For end of file byte in Range Specifications 2. and 3., HTTP_RANGE_REQUEST_END_OF_FILE should be passed.

Returns

Returns the following status codes: HTTPSuccess, if successful. HTTPInvalidParameter, if input parameters are invalid, including when the rangeStartOrlastNbytes and rangeEnd parameter combination is invalid. HTTPInsufficientMemory, if the passed HTTPRequestHeaders_t.pBuffer contains insufficient remaining memory for storing the range request.

HTTPClient_Send()

HTTPStatus_t HTTPClient_Send	(	const TransportInterface_t *	pTransport,
		HTTPRequestHeaders_t *	pRequestHeaders,
		const uint8_t *	pRequestBodyBuf,
		size_t	reqBodyBufLen,
		HTTPResponse_t *	pResponse,
		uint32_t	sendFlags
	)

Send the request headers in HTTPRequestHeaders_t.pBuffer and request body in pRequestBodyBuf over the transport. The response is received in HTTPResponse_t.pBuffer.

If HTTP_SEND_DISABLE_CONTENT_LENGTH_FLAG is not set in parameter sendFlags, then the Content-Length to be sent to the server is automatically written to pRequestHeaders. The Content-Length will not be written when there is no request body. If there is not enough room in the buffer to write the Content-Length then HTTPInsufficientMemory is returned. Please see HTTP_MAX_CONTENT_LENGTH_HEADER_LENGTH for the maximum Content-Length header field and value that could be written to the buffer.

The application should close the connection with the server if any of the following errors are returned:

• HTTPSecurityAlertResponseHeadersSizeLimitExceeded
• HTTPSecurityAlertExtraneousResponseData
• HTTPSecurityAlertInvalidChunkHeader
• HTTPSecurityAlertInvalidProtocolVersion
• HTTPSecurityAlertInvalidStatusCode
• HTTPSecurityAlertInvalidCharacter
• HTTPSecurityAlertInvalidContentLength

The pResponse returned is valid only if this function returns HTTPSuccess.

Parameters

[in]	pTransport	Transport interface, see TransportInterface_t for more information.
[in]	pRequestHeaders	Request configuration containing the buffer of headers to send.
[in]	pRequestBodyBuf	Optional Request entity body. Set to NULL if there is no request body.
[in]	reqBodyBufLen	The length of the request entity in bytes.
[in]	pResponse	The response message and some notable response parameters will be returned here on success.
[in]	sendFlags	Flags which modify the behavior of this function. Please see HTTPClient_Send Flags for more information.

Returns

One of the following:

• HTTPSuccess (If successful.)
• HTTPInvalidParameter (If any provided parameters or their members are invalid.)
• HTTPNetworkError (Errors in sending or receiving over the transport interface.)
• HTTPPartialResponse (Part of an HTTP response was received in a partially filled response buffer.)
• HTTPNoResponse (No data was received from the transport interface.)
• HTTPInsufficientMemory (The response received could not fit into the response buffer or extra headers could not be sent in the request.)
• HTTPParserInternalError (Internal parsing error.)
  
  Security alerts are listed below, please see HTTPStatus_t for more information:
• HTTPSecurityAlertResponseHeadersSizeLimitExceeded
• HTTPSecurityAlertExtraneousResponseData
• HTTPSecurityAlertInvalidChunkHeader
• HTTPSecurityAlertInvalidProtocolVersion
• HTTPSecurityAlertInvalidStatusCode
• HTTPSecurityAlertInvalidCharacter
• HTTPSecurityAlertInvalidContentLength

Example

// Variables used in this example.
HTTPStatus_t httpLibraryStatus = HTTPSuccess;
TransportInterface_t transportInterface = { 0 };
HTTPResponse_t = { 0 };
char requestBody[] = "This is an example request body.";
 
// Assume that requestHeaders has been initialized with
// HTTPClient_InitializeResponseHeaders() and any additional headers have
// been added with HTTPClient_AddHeader().
HTTPRequestHeaders_t requestHeaders;
 
// Set the transport interface with platform specific functions that are
// assumed to be implemented elsewhere.
transportInterface.recv = myPlatformTransportReceive;
transportInterface.send = myPlatformTransportSend;
transportInterface.pNetworkContext = myPlatformNetworkContext;
 
// Set the buffer to receive the HTTP response message into. The buffer is
// dynamically allocated for demonstration purposes only.
response.pBuffer = ( uint8_t* )malloc( 1024 );
response.bufferLen = 1024;
 
httpLibraryStatus = HTTPClient_Send( &transportInterface,
                                     &requestHeaders,
                                     requestBody,
                                     sizeof( requestBody ) - 1U,
                                     &response,
                                     0 );
 
if( httpLibraryStatus == HTTPSuccess )
{
    if( response.status == 200 )
    {
        // Handle a response Status-Code of 200 OK.
    }
}

HTTPClient_ReadHeader()

HTTPStatus_t HTTPClient_ReadHeader	(	const HTTPResponse_t *	pResponse,
		const char *	pField,
		size_t	fieldLen,
		const char **	pValueLoc,
		size_t *	pValueLen
	)

Read a header from a buffer containing a complete HTTP response. This will return the location of the response header value in the HTTPResponse_t.pBuffer buffer.

The location, within HTTPResponse_t.pBuffer, of the value found, will be returned in pValue. If the header value is empty for the found pField, then this function will return HTTPSuccess, and set the values for pValueLoc and pValueLen as NULL and zero respectively. According to RFC 2616, it is not invalid to have an empty value for some header fields.

Note

This function should only be called on a complete HTTP response. If the request is sent through the HTTPClient_Send function, the HTTPResponse_t is incomplete until HTTPClient_Send returns.

Parameters

[in]	pResponse	The buffer containing the completed HTTP response.
[in]	pField	The header field name to read.
[in]	fieldLen	The length of the header field name in bytes.
[out]	pValueLoc	This will be populated with the location of the header value in the response buffer, HTTPResponse_t.pBuffer.
[out]	pValueLen	This will be populated with the length of the header value in bytes.

Returns

One of the following:

• HTTPSuccess (If successful.)
• HTTPInvalidParameter (If any provided parameters or their members are invalid.)
• HTTPHeaderNotFound (Header is not found in the passed response buffer.)
• HTTPInvalidResponse (Provided response is not a valid HTTP response for parsing.)
• HTTPParserInternalError(If an error in the response parser.)

Example

HTTPStatus_t httpLibraryStatus = HTTPSuccess;
// Assume that response is returned from a successful invocation of
// HTTPClient_Send().
HTTPResponse_t response;
 
char * pDateLoc = NULL;
size_t dateLen = 0;
// Search for a "Date" header field. pDateLoc will be the location of the
// Date header value in response.pBuffer.
httpLibraryStatus = HTTPClient_ReadHeader( &response,
                                           "Date",
                                           sizeof("Date") - 1,
                                           &pDateLoc,
                                           &dateLen );

HTTPClient_strerror()

const char* HTTPClient_strerror

(

HTTPStatus_t

status

)

Error code to string conversion utility for HTTP Client library.

Note

This returns constant strings, which should not be modified.

Parameters

[in]

status

The status code to convert to a string.

Returns

The string representation of the status code.