diff --git a/components/esp_http_client/esp_http_client.c b/components/esp_http_client/esp_http_client.c
index f7886bf46..19efdcdc6 100644
--- a/components/esp_http_client/esp_http_client.c
+++ b/components/esp_http_client/esp_http_client.c
@@ -1083,6 +1083,7 @@ static esp_err_t esp_http_client_request_send(esp_http_client_handle_t client, i
 
     client->data_written_index = 0;
     client->data_write_left = client->post_len;
+    http_dispatch_event(client, HTTP_EVENT_HEADER_SENT, NULL, 0);
     client->state = HTTP_STATE_REQ_COMPLETE_HEADER;
     return ESP_OK;
 }
diff --git a/components/tcp_transport/CMakeLists.txt b/components/tcp_transport/CMakeLists.txt
index e8125a726..9c2ef846b 100644
--- a/components/tcp_transport/CMakeLists.txt
+++ b/components/tcp_transport/CMakeLists.txt
@@ -2,7 +2,8 @@ set(COMPONENT_SRCS "transport.c"
                    "transport_ssl.c"
                    "transport_tcp.c"
                    "transport_ws.c"
-                   "transport_utils.c")
+                   "transport_utils.c"
+                   "transport_strcasestr.c")
 
 set(COMPONENT_ADD_INCLUDEDIRS "include")
 
diff --git a/components/tcp_transport/transport_strcasestr.c b/components/tcp_transport/transport_strcasestr.c
new file mode 100644
index 000000000..80551a4b3
--- /dev/null
+++ b/components/tcp_transport/transport_strcasestr.c
@@ -0,0 +1,57 @@
+/*-
+ * Copyright (c) 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * The quadratic code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+/* Linear algorithm Copyright (C) 2008 Eric Blake
+ * Permission to use, copy, modify, and distribute the linear portion of
+ * software is freely granted, provided that this notice is preserved.
+ */
+#include "transport_strcasestr.h"
+#include <string.h>
+#include <ctype.h>
+
+char *transport_strcasestr(const char *buffer, const char *key)
+{
+    char c, sc;
+    size_t len;
+
+    if ((c = *key++) != 0) {
+        c = tolower((unsigned char)c);
+        len = strlen(key);
+        do {
+            do {
+                if ((sc = *buffer++) == 0)
+                    return (NULL);
+            } while ((char)tolower((unsigned char)sc) != c);
+        } while (strncasecmp(buffer, key, len) != 0);
+        buffer--;
+    }
+    return ((char *)buffer);
+}
diff --git a/components/tcp_transport/transport_strcasestr.h b/components/tcp_transport/transport_strcasestr.h
new file mode 100644
index 000000000..e337d90d5
--- /dev/null
+++ b/components/tcp_transport/transport_strcasestr.h
@@ -0,0 +1,38 @@
+/*-
+ * Copyright (c) 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * The quadratic code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+/* Linear algorithm Copyright (C) 2008 Eric Blake
+ * Permission to use, copy, modify, and distribute the linear portion of
+ * software is freely granted, provided that this notice is preserved.
+ */
+
+char *transport_strcasestr(const char *buffer, const char *key);
+
diff --git a/components/tcp_transport/transport_ws.c b/components/tcp_transport/transport_ws.c
index 55ea6d115..6480fb082 100644
--- a/components/tcp_transport/transport_ws.c
+++ b/components/tcp_transport/transport_ws.c
@@ -8,6 +8,7 @@
 #include "esp_transport_tcp.h"
 #include "esp_transport_ws.h"
 #include "esp_transport_utils.h"
+#include "transport_strcasestr.h"
 #include "mbedtls/base64.h"
 #include "mbedtls/sha1.h"
 
@@ -60,10 +61,9 @@ static char *trimwhitespace(const char *str)
     return (char *)str;
 }
 
-
 static char *get_http_header(const char *buffer, const char *key)
 {
-    char *found = strstr(buffer, key);
+    char *found = transport_strcasestr(buffer, key);
     if (found) {
         found += strlen(key);
         char *found_end = strstr(found, "\r\n");