TSMIMEHDRFIELDVALUESTRINGGET(3ts)

NAME
TSMimeHdrFieldValueStringGet - get HTTP MIME header values

SYNOPSIS

#include <ts/ts.h>

    const char * TSMimeHdrFieldValueStringGet(TSMBuffer bufp, TSMLoc hdr, TSMLoc field, int idx, int * value_len_ptr)

    int TSMimeHdrFieldValueIntGet(TSMBuffer bufp, TSMLoc hdr, TSMLoc field, int idx)

    int64_t TSMimeHdrFieldValueInt64Get(TSMBuffer bufp, TSMLoc hdr, TSMLoc field, int idx)

    unsigned int TSMimeHdrFieldValueUintGet(TSMBuffer bufp, TSMLoc hdr, TSMLoc field, int idx)

    time_t TSMimeHdrFieldValueDateGet(TSMBuffer bufp, TSMLoc hdr, TSMLoc field)

DESCRIPTION

MIME headers and fields can be components of request headers, response headers, or standalone headers created within a Traffic Server plugin. The functions here are all used to access header values of specific types, but it is up to the caller to know if a header has appropriate semantics for the API used. For all but TSMimeHdrFieldValueStringGet(), an appropriate data conversion algorithm is applied to the header field string.

All the APIs take a TSMBuffer marshal buffer argument bufp, and a TSMLoc argument hdr indicating the location of the HTTP headers. The required field argument is the locator of a specific header value, as returned by an accessor function such as TSMimeHdrFieldFind().

Within the header field, comma-separated values can be retrieved with an index idx ranging from 0 to the maximum number of fields for this value; this maximum is retrieved using TSMimeHdrFieldValuesCount(). An idx value of -1 has the semantics of retrieving the entire header value, regardless of how many comma-separated values there are. If a header is not comma-separated, an idx of 0 or -1 are the same, but the latter is preferred.

TSMimeHdrFieldValueStringGet() returns a pointer to the header value, and populated value_len_ptr with the length of the value in bytes. The returned header value is not NUL-terminated.

RETURN VALUES

All functions returns the header value with a type matching the respective function name. Using TSMimeHdrFieldValueDateGet() on a header which does not have date-time semantics always returns 0.

EXAMPLES

This examples show how to retrieve and copy a specific header.

        #include <string.h>
        #include <ts/ts.h>

        int
        get_content_type(TSHttpTxn txnp, char* buf, size_t buf_size)
        {
          TSMBuffer bufp;
          TSMLoc hdrs;
          TSMLoc ctype_field;
          int len = -1;

          if (TS_SUCCESS == TSHttpTxnServerRespGet(txnp, &bufp, &hdrs)) {
            ctype_field = TSMimeHdrFieldFind(bufp, hdrs, TS_MIME_FIELD_CONTENT_TYPE, TS_MIME_LEN_CONTENT_TYPE);

            if (TS_NULL_MLOC != ctype_field) {
              const char* str = TSMimeHdrFieldValueStringGet(bufp, hdrs, ctype_field, -1, &len);

              if (len > buf_size)
                len = buf_size;
              memcpy(buf, str, len);
              TSHandleMLocRelease(bufp, hdrs, ctype_field);
            }
            TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdrs);
          }

          return len;
        }

SEE SLSO

TSAPI(3ts), TSMBufferCreate(3ts), TSMimeHdrFieldValuesCount(3ts)

COPYRIGHT
2018, dev@trafficserver.apache.org