Add a simple http client. Since it uses libevent it's a better fit for btpd

than curl.

2 files changed, 494 insertions, 0 deletions

diff --git a/misc/http_client.c b/misc/http_client.c
new file mode 100644
index 0000000..2669213
--- /dev/null
+++ b/misc/http_client.c
@@ -0,0 +1,456 @@
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <sys/time.h>
+
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <event.h>
+#include <evdns.h>
+
+#include "subr.h"
+#include "http_client.h"
+
+struct http_url *
+http_url_parse(const char *url)
+{
+    size_t ulen = strlen(url);
+    if (strncmp(url, "http://", 7) != 0)
+        return NULL;
+    const char *cur, *at, *uri = NULL, *uri_e = NULL;
+    const char *host = NULL, *host_e = NULL;
+    const char *port = NULL, *port_e = NULL;
+    at = strchr(url + 7, '@');
+    uri = strchr(url + 7, '/');
+    cur = strchr(url + 7, '?');
+    if (cur != NULL && (uri == NULL || cur < uri))
+        uri = cur;
+    if (uri == NULL)
+        uri = url + ulen;
+    if (at != NULL && at < uri)
+        host = at + 1;
+    else
+        host = url + 7;
+    cur = host;
+    while (cur < uri && *cur != ':')
+        cur++;
+    host_e = cur;
+    if (host_e == host)
+        return NULL;
+    if (*cur == ':') {
+        cur++;
+        port = cur;
+        while (cur < uri && *cur >= '0' && *cur <= '9')
+            cur++;
+        if (cur == port || cur != uri)
+            return NULL;
+        port_e = cur;
+    }
+    while (*cur != '\0')
+        cur++;
+    uri_e = cur;
+    struct http_url *res =
+        malloc(sizeof(*res) + host_e - host + 1 + uri_e - uri + 2);
+    if (res == NULL)
+        return NULL;
+    if (port != NULL)
+        sscanf(port, "%hu", &res->port);
+    else
+        res->port = 80;
+    res->host = (char *)(res + 1);
+    res->uri = res->host + (host_e - host + 1);
+    bcopy(host, res->host, host_e - host);
+    res->host[host_e - host] = '\0';
+    if (*uri != '/') {
+        res->uri[0] = '/';
+        bcopy(uri, res->uri + 1, uri_e - uri);
+        res->uri[uri_e - uri + 1] = '\0';
+    } else {
+        bcopy(uri, res->uri, uri_e - uri);
+        res->uri[uri_e - uri] = '\0';
+    }
+    return res;
+}
+
+void
+http_url_free(struct http_url *url)
+{
+    free(url);
+}
+
+struct http_req {
+    enum {
+        HTTP_RESOLVE, HTTP_CONNECT, HTTP_WRITE, HTTP_RECEIVE, HTTP_PARSE
+    } state;
+    struct http_url *url;
+    int sd;
+    struct event ev;
+    http_cb cb;
+    void *arg;
+    int cancel;
+
+    int pstate, chunked;
+    long length;
+
+    struct evbuffer *buf;
+};
+
+static void
+http_free(struct http_req *req)
+{
+    if (req->url != NULL)
+        http_url_free(req->url);
+    if (req->buf != NULL)
+        evbuffer_free(req->buf);
+    if (req->sd > 0) {
+        event_del(&req->ev);
+        close(req->sd);
+    }
+    free(req);
+}
+
+static void
+http_error(struct http_req *req)
+{
+    struct http_response res;
+    res.type = HTTP_T_ERR;
+    res.v.error = 1;
+    req->cb(req, &res, req->arg);
+    http_free(req);
+}
+
+#define PS_HEAD  0
+#define PS_CHUNK_SIZE 1
+#define PS_CHUNK_DATA 2
+#define PS_CHUNK_CRLF 3
+#define PS_ID_DATA  4
+
+static int
+headers_parse(struct http_req *req, char *buf, char *end)
+{
+    int code;
+    char *cur, *crlf;
+    char name[128], value[872];
+    struct http_response res;
+
+    req->chunked = 0;
+    req->length = -1;
+
+    if (sscanf(buf, "HTTP/1.1 %d", &code) == 0)
+        return 0;
+    res.type = HTTP_T_CODE;
+    res.v.code = code;
+    req->cb(req, &res, req->arg);
+    if (req->cancel)
+        return 1;
+
+    cur = strstr(buf, "\r\n") + 2;
+    crlf = strstr(cur, "\r\n");
+    while (cur < end) {
+        int i;
+        char *colon = strchr(cur, ':');
+        if (colon == NULL || colon > crlf)
+            return 0;
+        snprintf(name, sizeof(name), "%.*s", (int)(colon - cur), cur);
+
+        cur = colon + 1;
+        i = 0;
+    val_loop:
+        while (isblank(*cur))
+            cur++;
+        while (cur < crlf) {
+            if (i < sizeof(value) - 1) {
+                value[i] = *cur;
+                i++;
+            }
+            cur++;
+        }
+        cur += 2;
+        crlf = strstr(cur, "\r\n");
+        if (isblank(*cur)) {
+            if (i < sizeof(value) - 1) {
+                value[i] = ' ';
+                i++;
+            }
+            cur++;
+            goto val_loop;
+        }
+        value[i] = '\0';
+        for (i--; i >= 0 && isblank(value[i]); i--)
+            value[i] = '\0';
+
+        res.type = HTTP_T_HEADER;
+        res.v.header.n = name;
+        res.v.header.v = value;
+        req->cb(req, &res, req->arg);
+        if (req->cancel)
+            return 1;
+        if ((!req->chunked
+                && strcasecmp("Transfer-Encoding", name) == 0
+                && strcasecmp("chunked", value) == 0))
+            req->chunked = 1;
+        if ((!req->chunked && req->length == -1
+                && strcasecmp("Content-Length", name) == 0)) {
+            errno = 0;
+            req->length = strtol(value, NULL, 10);
+            if (errno)
+                req->length = -1;
+        }
+    }
+    if (req->chunked)
+        req->pstate = PS_CHUNK_SIZE;
+    else
+        req->pstate = PS_ID_DATA;
+    return 1;
+}
+
+static int
+http_parse(struct http_req *req, int len)
+{
+    char *end, *numend;
+    size_t dlen;
+    struct http_response res;
+again:
+    switch (req->pstate) {
+    case PS_HEAD:
+        if (len == 0)
+            goto error;
+        if ((end = evbuffer_find(req->buf, "\r\n\r\n", 4)) == NULL) {
+            if (req->buf->off < (1 << 15))
+                return 1;
+            else
+                goto error;
+        }
+        if (evbuffer_add(req->buf, "", 1) != 0)
+            goto error;
+        req->buf->off--;
+        if (!headers_parse(req, req->buf->buffer, end))
+            goto error;
+        if (req->cancel)
+            goto cancel;
+        evbuffer_drain(req->buf, end - (char *)req->buf->buffer + 4);
+        goto again;
+    case PS_CHUNK_SIZE:
+        assert(req->chunked);
+        if (len == 0)
+            goto error;
+        if ((end = evbuffer_find(req->buf, "\r\n", 2)) == NULL) {
+            if (req->buf->off < 20)
+                return 1;
+            else
+                goto error;
+        }
+        errno = 0;
+        req->length = strtol(req->buf->buffer, &numend, 16);
+        if (req->length < 0 || numend == (char *)req->buf->buffer || errno)
+            goto error;
+        if (req->length == 0)
+            goto done;
+        evbuffer_drain(req->buf, end - (char *)req->buf->buffer + 2);
+        req->pstate = PS_CHUNK_DATA;
+        goto again;
+    case PS_CHUNK_DATA:
+        if (len == 0)
+            goto error;
+        assert(req->length > 0);
+        dlen = min(req->buf->off, req->length);
+        if (dlen > 0) {
+            res.type = HTTP_T_DATA;
+            res.v.data.l = dlen;
+            res.v.data.p = req->buf->buffer;
+            req->cb(req, &res, req->arg);
+            if (req->cancel)
+                goto cancel;
+            evbuffer_drain(req->buf, dlen);
+            req->length -= dlen;
+            if (req->length == 0) {
+                req->pstate = PS_CHUNK_CRLF;
+                goto again;
+            }
+        }
+        return 1;
+    case PS_CHUNK_CRLF:
+        if (len == 0)
+            goto error;
+        assert(req->length == 0);
+        if (req->buf->off < 2)
+            return 1;
+        if (bcmp(req->buf->buffer, "\r\n", 2) != 0)
+            goto error;
+        evbuffer_drain(req->buf, 2);
+        req->pstate = PS_CHUNK_SIZE;
+        goto again;
+    case PS_ID_DATA:
+        if (len == 0 && req->length < 0)
+            goto done;
+        else if (len == 0)
+            goto error;
+        if (req->length < 0)
+            dlen = req->buf->off;
+        else
+            dlen = min(req->buf->off, req->length);
+        if (dlen > 0) {
+            res.type = HTTP_T_DATA;
+            res.v.data.p = req->buf->buffer;
+            res.v.data.l = dlen;
+            req->cb(req, &res, req->arg);
+            if (req->cancel)
+                goto cancel;
+            evbuffer_drain(req->buf, dlen);
+            if (req->length > 0) {
+                req->length -= dlen;
+                if (req->length == 0)
+                    goto done;
+            }
+        }
+        return 1;
+    default:
+        abort();
+    }
+error:
+    http_error(req);
+    return 0;
+done:
+    res.type = HTTP_T_DONE;
+    req->cb(req, &res, req->arg);
+cancel:
+    http_free(req);
+    return 0;
+}
+
+static void
+http_read_cb(int sd, short type, void *arg)
+{
+    struct http_req *req = arg;
+    if (type == EV_TIMEOUT) {
+        http_error(req);
+        return;
+    }
+    int nr = evbuffer_read(req->buf, sd, 1 << 14);
+    if (nr < 0) {
+        if (nr == EAGAIN)
+            goto more;
+        else {
+            printf("read err\n");
+            http_error(req);
+            return;
+        }
+    }
+    req->state = HTTP_PARSE;
+    if (!http_parse(req, nr))
+        return;
+    req->state = HTTP_RECEIVE;
+more:
+    if (event_add(&req->ev, NULL) != 0)
+        http_error(req);
+}
+
+static void
+http_write_cb(int sd, short type, void *arg)
+{
+    struct http_req *req = arg;
+    if (type == EV_TIMEOUT) {
+        http_error(req);
+        return;
+    }
+    int nw = evbuffer_write(req->buf, sd);
+    if (nw == -1) {
+        if (errno == EAGAIN)
+            goto out;
+        else
+            goto error;
+    }
+out:
+    if (req->buf->off != 0) {
+        if (event_add(&req->ev, NULL) != 0)
+            goto error;
+    } else {
+        req->state = HTTP_RECEIVE;
+        event_set(&req->ev, req->sd, EV_READ, http_read_cb, req);
+        if (event_add(&req->ev, NULL) != 0)
+            goto error;
+    }
+    return;
+error:
+    printf("http write err\n");
+    http_error(req);
+}
+
+static void
+http_dnscb(int result, char type, int count, int ttl, void *addrs, void *arg)
+{
+    struct http_req *req = arg;
+    if (req->cancel)
+        http_free(req);
+    else if (result == 0 && type == 1 && count > 0) {
+        int addri = rand_between(0, count - 1);
+        struct sockaddr_in addr;
+        addr.sin_family = AF_INET;
+        addr.sin_port = htons(req->url->port);
+        bcopy(addrs + addri * 4, &addr.sin_addr.s_addr, 4);
+        req->state = HTTP_CONNECT;
+        if ((req->sd = socket(PF_INET, SOCK_STREAM, 0)) == -1)
+            goto error;
+        if (set_nonblocking(req->sd) != 0)
+            goto error;
+        if ((connect(req->sd, (struct sockaddr *)&addr, sizeof(addr)) != 0
+                && errno != EINPROGRESS))
+            goto error;
+        event_set(&req->ev, req->sd, EV_WRITE, http_write_cb, req);
+        if (event_add(&req->ev, NULL) != 0)
+            goto error;
+    } else
+        goto error;
+    return;
+
+error:
+    http_error(req);
+}
+
+int
+http_get(struct http_req **out, const char *url, const char *hdrs, http_cb cb,
+    void *arg)
+{
+    struct http_req *req = calloc(1, sizeof(*req));
+    if (req == NULL)
+        return 0;
+    req->sd = -1;
+    req->cb = cb;
+    req->arg = arg;
+    req->url = http_url_parse(url);
+    if (req->url == NULL)
+        goto error;
+    if ((req->buf = evbuffer_new()) == NULL)
+        goto error;
+    if (evbuffer_add_printf(req->buf, "GET %s HTTP/1.1\r\n"
+            "Accept-Encoding:\r\n"
+            "Connection: close\r\n"
+            "Host: %s\r\n"
+            "%s"
+            "\r\n", req->url->uri, req->url->host, hdrs) == -1)
+        goto error;
+    if (evdns_resolve_ipv4(req->url->host, 0, http_dnscb, req) != 0)
+        goto error;
+    if (out != NULL)
+        *out = req;
+    return 1;
+error:
+    http_free(req);
+    return 0;
+}
+
+void
+http_cancel(struct http_req *req)
+{
+    if (req->state == HTTP_RESOLVE || req->state == HTTP_PARSE)
+        req->cancel = 1;
+    else
+        http_free(req);
+}
diff --git a/misc/http_client.h b/misc/http_client.h
new file mode 100644
index 0000000..2d0c24a
--- /dev/null
+++ b/misc/http_client.h
@@ -0,0 +1,38 @@
+#ifndef BTPD_HTTP_CLIENT_H
+#define BTPD_HTTP_CLIENT_H
+
+struct http_response {
+    enum {
+        HTTP_T_ERR, HTTP_T_CODE, HTTP_T_HEADER, HTTP_T_DATA, HTTP_T_DONE
+    } type;
+    union {
+        int error;
+        int code;
+        struct {
+            char *n;
+            char *v;
+        } header;
+        struct {
+            size_t l;
+            char *p;
+        } data;
+    } v;
+};
+
+struct http_url {
+    char *host;
+    char *uri;
+    uint16_t port;
+};
+
+struct http_req;
+
+typedef void (*http_cb)(struct http_req *, struct http_response *, void *);
+
+struct http_url *http_url_parse(const char *url);
+void http_url_free(struct http_url *url);
+int http_get(struct http_req **out, const char *url, const char *hdrs,
+    http_cb cb, void *arg);
+void http_cancel(struct http_req *req);
+
+#endif