MINOR: httpclient: implement a simple HTTP Client API
This commit implements a very simple HTTP Client API.
A client can be operated by several functions:
- httpclient_new(), httpclient_destroy(): create
and destroy the struct httpclient instance.
- httpclient_req_gen(): generate a complete HTX request using the
the absolute URL, the method and a list of headers. This request
is complete and sets the HTX End of Message flag. This is limited
to small request we don't need a body.
- httpclient_start() fill a sockaddr storage with a IP extracted
from the URL (it cannot resolve an fqdm for now), start the
applet. It also stores the ptr of the caller which could be an
appctx or something else.
- hc->ops contains a list of callbacks used by the
HTTPClient, they should be filled manually after an
httpclient_new():
* res_stline(): the client received a start line, its content
will be stored in hc->res.vsn, hc->res.status, hc->res.reason
* res_headers(): the client received headers, they are stored in
hc->res.hdrs.
* res_payload(): the client received some payload data, they are
stored in the hc->res.buf buffer and could be extracted with the
httpclient_res_xfer() function, which takes a destination buffer
as a parameter
* res_end(): this callback is called once we finished to receive
the response.
diff --git a/include/haproxy/applet-t.h b/include/haproxy/applet-t.h
index d04c3c8..222ad6d 100644
--- a/include/haproxy/applet-t.h
+++ b/include/haproxy/applet-t.h
@@ -190,6 +190,9 @@
struct {
void *ptr;
} sft; /* sink forward target */
+ struct {
+ struct httpclient *ptr;
+ } httpclient;
/* NOTE: please add regular applet contexts (ie: not
* CLI-specific ones) above, before "cli".
diff --git a/include/haproxy/http_client-t.h b/include/haproxy/http_client-t.h
new file mode 100644
index 0000000..079afdc
--- /dev/null
+++ b/include/haproxy/http_client-t.h
@@ -0,0 +1,42 @@
+#ifndef _HAPROXY_HTTPCLIENT_T_H
+#define _HAPROXY_HTTPCLIENT_T_H
+
+#include <haproxy/http-t.h>
+
+struct httpclient {
+ struct {
+ struct ist url; /* URL of the request */
+ enum http_meth_t meth; /* method of the request */
+ struct buffer buf; /* output buffer */
+ } req;
+ struct {
+ struct ist vsn;
+ uint16_t status;
+ struct ist reason;
+ struct http_hdr *hdrs; /* headers */
+ struct buffer buf; /* input buffer */
+ } res;
+ struct {
+ /* callbacks used to receive the response, if not set, the IO
+ * handler will consume the data without doing anything */
+ void (*res_stline)(struct httpclient *hc); /* start line received */
+ void (*res_headers)(struct httpclient *hc); /* headers received */
+ void (*res_payload)(struct httpclient *hc); /* payload received */
+ void (*res_end)(struct httpclient *hc); /* end of the response */
+ } ops;
+ struct sockaddr_storage dst; /* destination address */
+ struct appctx *appctx; /* HTTPclient appctx */
+ void *caller; /* ptr of the caller */
+};
+
+/* States of the HTTP Client Appctx */
+enum {
+ HTTPCLIENT_S_REQ = 0,
+ HTTPCLIENT_S_RES_STLINE,
+ HTTPCLIENT_S_RES_HDR,
+ HTTPCLIENT_S_RES_BODY,
+ HTTPCLIENT_S_RES_END,
+};
+
+
+#endif /* ! _HAPROXY_HTTCLIENT__T_H */
diff --git a/include/haproxy/http_client.h b/include/haproxy/http_client.h
new file mode 100644
index 0000000..2f507dd
--- /dev/null
+++ b/include/haproxy/http_client.h
@@ -0,0 +1,11 @@
+#ifndef _HAPROXY_HTTPCLIENT_H
+#define _HAPROXY_HTTPCLIENT_H
+
+void httpclient_destroy(struct httpclient *hc);
+struct httpclient *httpclient_new(void *caller, enum http_meth_t meth, struct ist url);
+
+struct appctx *httpclient_start(struct httpclient *hc);
+int httpclient_res_xfer(struct httpclient *hc, struct buffer *dst);
+int httpclient_req_gen(struct httpclient *hc, const struct ist url, enum http_meth_t meth, const struct http_hdr *hdrs);
+
+#endif /* ! _HAPROXY_HTTCLIENT_H */
diff --git a/src/http_client.c b/src/http_client.c
index 4a95b92..9f148b4 100644
--- a/src/http_client.c
+++ b/src/http_client.c
@@ -12,13 +12,23 @@
*
*/
#include <haproxy/connection-t.h>
+#include <haproxy/http_client-t.h>
#include <haproxy/server-t.h>
+#include <haproxy/applet.h>
+#include <haproxy/cli.h>
+#include <haproxy/dynbuf.h>
#include <haproxy/cfgparse.h>
#include <haproxy/connection.h>
#include <haproxy/global.h>
+#include <haproxy/h1_htx.h>
+#include <haproxy/http.h>
+#include <haproxy/http_client.h>
+#include <haproxy/http_htx.h>
+#include <haproxy/htx.h>
#include <haproxy/log.h>
#include <haproxy/proxy.h>
+#include <haproxy/stream_interface.h>
#include <haproxy/tools.h>
#include <string.h>
@@ -28,6 +38,413 @@
static struct server *httpclient_srv_raw;
static struct server *httpclient_srv_ssl;
+static struct applet httpclient_applet;
+
+/*
+ * Generate a simple request and fill the httpclient request buffer with it.
+ * The request contains a request line generated from the absolute <url> and
+ * <meth> as well as list of headers <hdrs>.
+ *
+ * If the buffer was filled correctly the function returns 0, if not it returns
+ * an error_code but there is no guarantee that the buffer wasn't modified.
+ */
+int httpclient_req_gen(struct httpclient *hc, const struct ist url, enum http_meth_t meth, const struct http_hdr *hdrs)
+{
+ struct htx_sl *sl;
+ struct htx *htx;
+ int err_code = 0;
+ struct ist meth_ist, vsn;
+ unsigned int flags = HTX_SL_F_VER_11 | HTX_SL_F_BODYLESS | HTX_SL_F_XFER_LEN | HTX_SL_F_NORMALIZED_URI | HTX_SL_F_HAS_SCHM;
+
+ if (meth >= HTTP_METH_OTHER)
+ goto error;
+
+ meth_ist = http_known_methods[meth];
+
+ vsn = ist("HTTP/1.1");
+
+ htx = htx_from_buf(&hc->req.buf);
+ if (!htx)
+ goto error;
+ sl = htx_add_stline(htx, HTX_BLK_REQ_SL, flags, meth_ist, url, vsn);
+ if (!sl) {
+ goto error;
+ }
+ sl->info.req.meth = meth;
+
+ /* Add Host Header from URL */
+ if (!http_update_host(htx, sl, url))
+ goto error;
+
+ /* add the headers and EOH */
+ if (hdrs && !htx_add_all_headers(htx, hdrs))
+ goto error;
+
+ htx->flags |= HTX_FL_EOM;
+
+ htx_to_buf(htx, &hc->req.buf);
+
+ return 0;
+error:
+ err_code |= ERR_ALERT | ERR_ABORT;
+ return err_code;
+}
+
+/*
+ * transfer the response to the destination buffer and wakeup the HTTP client
+ * applet so it could fill again its buffer.
+ *
+ * Return the number of bytes transfered.
+ */
+int httpclient_res_xfer(struct httpclient *hc, struct buffer *dst)
+{
+ int ret;
+
+ ret = b_xfer(dst, &hc->res.buf, MIN(1024, b_data(&hc->res.buf)));
+ /* call the client once we consumed all data */
+ if (!b_data(&hc->res.buf) && hc->appctx)
+ appctx_wakeup(hc->appctx);
+ return ret;
+}
+
+/*
+ * Start the HTTP client
+ * Create the appctx, session, stream and wakeup the applet
+ *
+ * FIXME: It also fill the sockaddr with the IP address, but currently only IP
+ * in the URL are supported, it lacks a resolver.
+ *
+ * Return the <appctx> or NULL if it failed
+ */
+struct appctx *httpclient_start(struct httpclient *hc)
+{
+ struct applet *applet = &httpclient_applet;
+ struct appctx *appctx;
+ struct session *sess;
+ struct stream *s;
+ int len;
+ struct split_url out;
+
+ /* parse URI and fill sockaddr_storage */
+ /* FIXME: use a resolver */
+ len = url2sa(ist0(hc->req.url), istlen(hc->req.url), &hc->dst, &out);
+ if (len == -1) {
+ ha_alert("httpclient: cannot parse uri '%s'.\n", ist0(hc->req.url));
+ goto out;
+ }
+
+ /* The HTTP client will be created in the same thread as the caller,
+ * avoiding threading issues */
+ appctx = appctx_new(applet, tid_bit);
+ if (!appctx)
+ goto out;
+
+ sess = session_new(httpclient_proxy, NULL, &appctx->obj_type);
+ if (!sess) {
+ ha_alert("httpclient: out of memory in %s:%d.\n", __FUNCTION__, __LINE__);
+ goto out_free_appctx;
+ }
+ if ((s = stream_new(sess, &appctx->obj_type, &BUF_NULL)) == NULL) {
+ ha_alert("httpclient: Failed to initialize stream %s:%d.\n", __FUNCTION__, __LINE__);
+ goto out_free_appctx;
+ }
+
+ if (!sockaddr_alloc(&s->target_addr, &hc->dst, sizeof(hc->dst))) {
+ ha_alert("httpclient: Failed to initialize stream in %s:%d.\n", __FUNCTION__, __LINE__);
+ goto out_free_stream;
+ }
+
+ /* choose the SSL server or not */
+ switch (out.scheme) {
+ case SCH_HTTP:
+ s->target = &httpclient_srv_raw->obj_type;
+ break;
+ case SCH_HTTPS:
+ s->target = &httpclient_srv_ssl->obj_type;
+ break;
+ }
+
+ s->flags |= SF_ASSIGNED|SF_ADDR_SET;
+ s->si[1].flags |= SI_FL_NOLINGER;
+ s->res.flags |= CF_READ_DONTWAIT;
+
+ /* applet is waiting for data */
+ si_cant_get(&s->si[0]);
+ appctx_wakeup(appctx);
+
+ task_wakeup(s->task, TASK_WOKEN_INIT);
+ hc->appctx = appctx;
+ appctx->ctx.httpclient.ptr = hc;
+ appctx->st0 = HTTPCLIENT_S_REQ;
+
+ return appctx;
+
+out_free_stream:
+ LIST_DELETE(&s->list);
+ pool_free(pool_head_stream, s);
+out_free_sess:
+ session_free(sess);
+out_free_appctx:
+ appctx_free(appctx);
+out:
+
+ return NULL;
+}
+
+/* Free the httpclient */
+void httpclient_destroy(struct httpclient *hc)
+{
+ if (!hc)
+ return;
+ b_free(&hc->req.buf);
+ b_free(&hc->res.buf);
+ free(hc);
+
+ return;
+}
+
+/* Allocate an httpclient and its buffers
+ * Return NULL on failure */
+struct httpclient *httpclient_new(void *caller, enum http_meth_t meth, struct ist url)
+{
+ struct httpclient *hc;
+ struct buffer *b;
+
+ hc = calloc(1, sizeof(*hc));
+ if (!hc)
+ goto err;
+
+ b = b_alloc(&hc->req.buf);
+ if (!b)
+ goto err;
+ b = b_alloc(&hc->res.buf);
+ if (!b)
+ goto err;
+
+ hc->caller = caller;
+ hc->req.url = url;
+ hc->req.meth = meth;
+
+ return hc;
+
+err:
+ httpclient_destroy(hc);
+ return NULL;
+}
+
+static void httpclient_applet_io_handler(struct appctx *appctx)
+{
+ struct httpclient *hc = appctx->ctx.httpclient.ptr;
+ struct stream_interface *si = appctx->owner;
+ struct stream *s = si_strm(si);
+ struct channel *req = &s->req;
+ struct channel *res = &s->res;
+ struct htx_blk *blk = NULL;
+ struct htx *htx;
+ struct htx_sl *sl;
+ int32_t pos;
+ uint32_t hdr_num;
+
+
+ while (1) {
+ switch(appctx->st0) {
+
+ case HTTPCLIENT_S_REQ:
+ /* copy the request from the hc->req.buf buffer */
+ htx = htx_from_buf(&req->buf);
+ /* We now that it fits the content of a buffer so can
+ * just push this entirely */
+ b_xfer(&req->buf, &hc->req.buf, b_data(&hc->req.buf));
+ channel_add_input(req, b_data(&req->buf));
+ appctx->st0 = HTTPCLIENT_S_RES_STLINE;
+ goto more; /* we need to leave the IO handler once we wrote the request */
+ break;
+
+ case HTTPCLIENT_S_RES_STLINE:
+ /* copy the start line in the hc structure,then remove the htx block */
+ if (!b_data(&res->buf))
+ goto more;
+ htx = htxbuf(&res->buf);
+ if (!htx)
+ goto more;
+ blk = htx_get_first_blk(htx);
+ if (blk && (htx_get_blk_type(blk) == HTX_BLK_RES_SL))
+ sl = htx_get_blk_ptr(htx, blk);
+ if (!sl || (!(sl->flags & HTX_SL_F_IS_RESP)))
+ goto more;
+
+ /* copy the status line in the httpclient */
+ hc->res.status = sl->info.res.status;
+ hc->res.vsn = istdup(htx_sl_res_vsn(sl));
+ hc->res.reason = istdup(htx_sl_res_reason(sl));
+ co_htx_remove_blk(res, htx, blk);
+ /* caller callback */
+ if (hc->ops.res_stline)
+ hc->ops.res_stline(hc);
+
+ /* if there is no HTX data anymore and the EOM flag is
+ * set, leave (no body) */
+ if (htx_is_empty(htx) && htx->flags & HTX_FL_EOM)
+ appctx->st0 = HTTPCLIENT_S_RES_END;
+ else
+ appctx->st0 = HTTPCLIENT_S_RES_HDR;
+ break;
+
+ case HTTPCLIENT_S_RES_HDR:
+ /* first copy the headers in a local hdrs
+ * structure, once we the total numbers of the
+ * header we allocate the right size and copy
+ * them. The htx block of the headers are
+ * removed each time one is read */
+ {
+ struct http_hdr hdrs[global.tune.max_http_hdr];
+
+ if (!b_data(&res->buf))
+ goto more;
+ htx = htxbuf(&res->buf);
+ if (!htx)
+ goto more;
+
+ hdr_num = 0;
+
+ for (pos = htx_get_first(htx); pos != -1; pos = htx_get_next(htx, pos)) {
+ struct htx_blk *blk = htx_get_blk(htx, pos);
+ enum htx_blk_type type = htx_get_blk_type(blk);
+
+ if (type == HTX_BLK_EOH) {
+ hdrs[hdr_num].n = IST_NULL;
+ hdrs[hdr_num].v = IST_NULL;
+ co_htx_remove_blk(res, htx, blk);
+ break;
+ }
+
+ if (type != HTX_BLK_HDR)
+ continue;
+
+ hdrs[hdr_num].n = istdup(htx_get_blk_name(htx, blk));
+ hdrs[hdr_num].v = istdup(htx_get_blk_value(htx, blk));
+ if (!isttest(hdrs[hdr_num].v) || !isttest(hdrs[hdr_num].n))
+ goto end;
+ co_htx_remove_blk(res, htx, blk);
+ hdr_num++;
+ }
+
+ /* alloc and copy the headers in the httpclient struct */
+ hc->res.hdrs = calloc((hdr_num + 1), sizeof(*hc->res.hdrs));
+ if (!hc->res.hdrs)
+ goto end;
+ memcpy(hc->res.hdrs, hdrs, sizeof(struct http_hdr) * (hdr_num + 1));
+
+ /* caller callback */
+ if (hc->ops.res_headers)
+ hc->ops.res_headers(hc);
+
+ /* if there is no HTX data anymore and the EOM flag is
+ * set, leave (no body) */
+ if (htx_is_empty(htx) && htx->flags & HTX_FL_EOM)
+ appctx->st0 = HTTPCLIENT_S_RES_END;
+ else
+ appctx->st0 = HTTPCLIENT_S_RES_BODY;
+ }
+ break;
+
+ case HTTPCLIENT_S_RES_BODY:
+ /*
+ * The IO handler removes the htx blocks in the response buffer and
+ * push them in the hc->res.buf buffer in a raw format.
+ */
+ htx = htxbuf(&res->buf);
+ if (!htx || htx_is_empty(htx))
+ goto more;
+
+ if (b_full(&hc->res.buf))
+ goto process_data;
+
+ /* decapsule the htx data to raw data */
+ for (pos = htx_get_first(htx); pos != -1; pos = htx_get_next(htx, pos)) {
+ enum htx_blk_type type;
+
+ blk = htx_get_blk(htx, pos);
+ type = htx_get_blk_type(blk);
+ if (type == HTX_BLK_DATA) {
+ struct ist v = htx_get_blk_value(htx, blk);
+
+ if ((b_room(&hc->res.buf) < v.len) )
+ goto process_data;
+
+ __b_putblk(&hc->res.buf, v.ptr, v.len);
+ co_htx_remove_blk(res, htx, blk);
+ /* the data must be processed by the caller in the receive phase */
+ if (hc->ops.res_payload)
+ hc->ops.res_payload(hc);
+ } else {
+ /* remove any block which is not a data block */
+ co_htx_remove_blk(res, htx, blk);
+ }
+ }
+ /* if not finished, should be called again */
+ if (!(htx->flags & HTX_FL_EOM))
+ goto more;
+
+ /* end of message, we should quit */
+ appctx->st0 = HTTPCLIENT_S_RES_END;
+ break;
+
+ case HTTPCLIENT_S_RES_END:
+ goto end;
+ break;
+ }
+ }
+
+process_data:
+
+ si_rx_chan_rdy(si);
+
+ return;
+more:
+ /* There was not enough data in the response channel */
+
+ si_rx_room_blk(si);
+
+ if (appctx->st0 == HTTPCLIENT_S_RES_END)
+ goto end;
+
+ /* The state machine tries to handle as much data as possible, if there
+ * isn't any data to handle and a shutdown is detected, let's stop
+ * everything */
+ if ((req->flags & (CF_SHUTR|CF_SHUTR_NOW)) ||
+ (res->flags & (CF_SHUTW|CF_SHUTW_NOW))) {
+ goto end;
+ }
+ return;
+
+end:
+ if (hc->ops.res_end)
+ hc->ops.res_end(hc);
+ si_shutw(si);
+ si_shutr(si);
+ return;
+}
+
+static void httpclient_applet_release(struct appctx *appctx)
+{
+ struct httpclient *hc = appctx->ctx.httpclient.ptr;
+
+ /* the applet is leaving, remove the ptr so we don't try to call it
+ * again from the caller */
+ hc->appctx = NULL;
+
+ return;
+}
+
+/* HTTP client applet */
+static struct applet httpclient_applet = {
+ .obj_type = OBJ_TYPE_APPLET,
+ .name = "<HTTPCLIENT>",
+ .fct = httpclient_applet_io_handler,
+ .release = httpclient_applet_release,
+};
+
/*
* Initialize the proxy for the HTTP client with 2 servers, one for raw HTTP,
* the other for HTTPS.
@@ -98,10 +515,6 @@
return err_code;
}
-/*
- * Post config parser callback, this is used to copy the log line from the
- * global section and put it in the server proxy
- */
static int httpclient_cfg_postparser()
{
struct logsrv *logsrv;