//响应添加报文头
TSReturnCode StaSerRespMimeHdrFieldAppend(TSHttpTxn txnp,char *name,int name_length,char *value,int value_len)
{
	TSMBuffer bufp;
    TSMLoc hdr_loc;
    TSMLoc field_loc;
	if (TSHttpTxnServerRespGet(txnp, &bufp, &hdr_loc) != TS_SUCCESS) {
		return TS_ERROR;
	}
	field_loc = TSMimeHdrFieldFind(bufp, hdr_loc, name, name_length);
	if(field_loc != TS_NULL_MLOC){
	    TSMimeHdrFieldValuesClear(bufp, hdr_loc, field_loc);
	    TSMimeHdrFieldValueStringInsert(bufp, hdr_loc, field_loc, -1, value, value_len);
	    TSHandleMLocRelease(bufp, hdr_loc, field_loc);
	}else{
		if (TSMimeHdrFieldCreate(bufp, hdr_loc, &field_loc) != TS_SUCCESS) {
			return TS_ERROR;
		}
		TSMimeHdrFieldAppend(bufp, hdr_loc, field_loc);
		TSMimeHdrFieldValuesClear(bufp, hdr_loc, field_loc);
		TSMimeHdrFieldNameSet(bufp, hdr_loc, field_loc, name, name_length);
		TSMimeHdrFieldValueStringInsert(bufp, hdr_loc, field_loc, -1, value, value_len);
		TSHandleMLocRelease(bufp, hdr_loc, field_loc);
	}
	TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
	return TS_SUCCESS;
}
static void
replace_header(TSHttpTxn txnp)
{
    TSMBuffer resp_bufp;
    TSMLoc resp_loc;
    TSMLoc field_loc;

    if (TSHttpTxnServerRespGet(txnp, &resp_bufp, &resp_loc) != TS_SUCCESS) {
        TSError("couldn't retrieve server response header.\n");
        goto done;
    }

    field_loc = TSMimeHdrFieldFind(resp_bufp, resp_loc, TS_MIME_FIELD_ACCEPT_RANGES, TS_MIME_LEN_ACCEPT_RANGES);
    if (field_loc == TS_NULL_MLOC) {
        /* field was not found */

        /* create a new field in the header */
        TSMimeHdrFieldCreate(resp_bufp, resp_loc, &field_loc); /* Probably should check for errors. */
        /* set its name */
        TSMimeHdrFieldNameSet(resp_bufp, resp_loc, field_loc, TS_MIME_FIELD_ACCEPT_RANGES, TS_MIME_LEN_ACCEPT_RANGES);
        /* set its value */
        TSMimeHdrFieldValueAppend(resp_bufp, resp_loc, field_loc, -1, "none", 4);
        /* insert it into the header */
        TSMimeHdrFieldAppend(resp_bufp, resp_loc, field_loc);
        TSHandleMLocRelease(resp_bufp, resp_loc, field_loc);
        TSHandleMLocRelease(resp_bufp, TS_NULL_MLOC, resp_loc);
    } else {
        /* clear the field */
        TSMimeHdrFieldValuesClear(resp_bufp, resp_loc, field_loc);
        /* set the value to "none" */
        TSMimeHdrFieldValueStringInsert(resp_bufp, resp_loc, field_loc, -1, "none", 4);
        TSHandleMLocRelease(resp_bufp, resp_loc, field_loc);
        TSHandleMLocRelease(resp_bufp, TS_NULL_MLOC, resp_loc);
    }

done:
    TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
}