[Olsr-dev] [PATCH] jsoninfo: HTTP headers with CORS (if requested)

Alessio Caiazza (spam-protected)
Fri May 16 17:59:25 CEST 2014


The new "httpheaders" parameter prepends HTTP headers to the reply.
If not set it will default to "no" and have the same behaviour as before.
Cross-origin resource sharing headers (CORS) are included in reply allowing the
json retrieval by javascript applications not served by olsrd itself.
This will allow to easily develop js applications running directly in the
browser.
---
 lib/jsoninfo/README_JSONINFO      |  8 +++++
 lib/jsoninfo/src/olsrd_jsoninfo.c | 68 +++++++++++++++++++++++++++++++++++++--
 lib/jsoninfo/src/olsrd_jsoninfo.h |  1 +
 lib/jsoninfo/src/olsrd_plugin.c   | 17 ++++++++++
 4 files changed, 91 insertions(+), 3 deletions(-)

diff --git a/lib/jsoninfo/README_JSONINFO b/lib/jsoninfo/README_JSONINFO
index a102a56..4e63859 100644
--- a/lib/jsoninfo/README_JSONINFO
+++ b/lib/jsoninfo/README_JSONINFO
@@ -73,6 +73,14 @@ LoadPlugin "olsrd_jsoninfo.so.0.0"
     # if you set it to 0.0.0.0, it will accept all connections
     #PlParam      "accept" "0.0.0.0"
 
+    # The "httpheaders" parameter prepends HTTP headers to the reply.
+    # If not set it will default to "no" and have the same behaviour as before.
+    # Among with a minimal set of headers also Cross-origin resource sharing
+    # headers (CORS) are included in reply allowing the json retrieval by
+    # javascript applications not served by olsrd itself.
+    # You can enable it uncommenting the following line:
+    #PlParam      "httpheaders" "yes"
+
     # specify a UUID for this node to track it for debugging
     #PlParam      "UUIDFile" "/etc/olsrd/olsrd.uuid"
 }
diff --git a/lib/jsoninfo/src/olsrd_jsoninfo.c b/lib/jsoninfo/src/olsrd_jsoninfo.c
index 9db99b8..c9d1284 100644
--- a/lib/jsoninfo/src/olsrd_jsoninfo.c
+++ b/lib/jsoninfo/src/olsrd_jsoninfo.c
@@ -96,6 +96,9 @@
 
 static int ipc_socket;
 
+/**Response types */
+#define HTTP_200 "HTTP/1.1 200 OK"
+
 /* IPC initialization function */
 static int plugin_ipc_init(void);
 
@@ -126,6 +129,9 @@ static void ipc_print_interfaces(struct autobuf *);
 static void ipc_print_plugins(struct autobuf *);
 static void ipc_print_olsrd_conf(struct autobuf *abuf);
 
+static size_t build_http_header(const char *status, const char *mime,
+  uint32_t msgsize, char *buf, uint32_t bufsize);
+
 #define TXT_IPC_BUFSIZE 256
 
 /* these provide all of the runtime status info */
@@ -151,6 +157,7 @@ static void ipc_print_olsrd_conf(struct autobuf *abuf);
 #define SIW_OLSRD_CONF 0x1000
 
 #define MAX_CLIENTS 3
+#define MAX_HTTPHEADER_SIZE 1024
 
 static char *outbuffer[MAX_CLIENTS];
 static size_t outbuffer_size[MAX_CLIENTS];
@@ -1282,6 +1289,9 @@ static void
 send_info(unsigned int send_what, int the_socket)
 {
   struct autobuf abuf;
+  size_t header_len = 0;
+  char header_buf[MAX_HTTPHEADER_SIZE];
+  const char *content_type = "application/json";
 
   /* global variables for tracking when to put a comma in for JSON */
   entrynumber[0] = 0;
@@ -1320,12 +1330,17 @@ send_info(unsigned int send_what, int the_socket)
     ipc_print_olsrd_conf(&abuf);
   }
 
-  outbuffer[outbuffer_count] = olsr_malloc(abuf.len, "txt output buffer");
-  outbuffer_size[outbuffer_count] = abuf.len;
+  if(http_headers) {
+    header_len = build_http_header(HTTP_200, content_type, abuf.len, header_buf, sizeof(header_buf));
+  }
+
+  outbuffer[outbuffer_count] = olsr_malloc(header_len + abuf.len, "json output buffer");
+  outbuffer_size[outbuffer_count] = header_len + abuf.len;
   outbuffer_written[outbuffer_count] = 0;
   outbuffer_socket[outbuffer_count] = the_socket;
 
-  memcpy(outbuffer[outbuffer_count], abuf.buf, abuf.len);
+  memcpy(outbuffer[outbuffer_count], header_buf, header_len);
+  memcpy((outbuffer[outbuffer_count]) + header_len, abuf.buf, abuf.len);
   outbuffer_count++;
 
   if (outbuffer_count == 1) {
@@ -1340,6 +1355,53 @@ send_info(unsigned int send_what, int the_socket)
   abuf_free(&abuf);
 }
 
+static size_t
+build_http_header(const char *status, const char *mime, uint32_t msgsize,
+  char *buf, uint32_t bufsize)
+{
+  time_t currtime;
+  size_t size;
+
+  size = snprintf(buf, bufsize, "%s\r\n", status);
+
+  /* Date */
+  time(&currtime);
+  size += strftime(&buf[size], bufsize - size, "Date: %a, %d %b %Y %H:%M:%S GMT\r\n", localtime(&currtime));
+
+  /* Server version */
+  size += snprintf(&buf[size], bufsize - size, "Server: OLSRD JSONInfo plugin\r\n");
+
+  /* connection-type */
+  size += snprintf(&buf[size], bufsize - size, "Connection: closed\r\n");
+
+  /* MIME type */
+  if(mime != NULL) {
+    size += snprintf(&buf[size], bufsize - size, "Content-type: %s\r\n", mime);
+  }
+
+  /* CORS data */
+  /**No needs to be strict here, access control is based on source IP*/
+  size += snprintf(&buf[size], bufsize - size, "Access-Control-Allow-Origin: *\r\n");
+  size += snprintf(&buf[size], bufsize - size, "Access-Control-Allow-Methods: GET, POST, OPTIONS\r\n");
+  size += snprintf(&buf[size], bufsize - size, "Access-Control-Allow-Headers: Accept, Origin, X-Requested-With\r\n");
+  size += snprintf(&buf[size], bufsize - size, "Access-Control-Max-Age: 1728000\r\n");
+
+  /* Content length */
+  if (msgsize > 0) {
+    size += snprintf(&buf[size], bufsize - size, "Content-length: %i\r\n", msgsize);
+  }
+
+  /* Cache-control
+   * No caching dynamic pages
+   */
+  size += snprintf(&buf[size], bufsize - size, "Cache-Control: no-cache\r\n");
+
+  /* End header */
+  size += snprintf(&buf[size], bufsize - size, "\r\n");
+
+  return size;
+}
+
 /*
  * Local Variables:
  * mode: c
diff --git a/lib/jsoninfo/src/olsrd_jsoninfo.h b/lib/jsoninfo/src/olsrd_jsoninfo.h
index 8478f62..56acb70 100644
--- a/lib/jsoninfo/src/olsrd_jsoninfo.h
+++ b/lib/jsoninfo/src/olsrd_jsoninfo.h
@@ -62,6 +62,7 @@ extern union olsr_ip_addr jsoninfo_accept_ip;
 extern union olsr_ip_addr jsoninfo_listen_ip;
 extern int ipc_port;
 extern int nompr;
+extern bool http_headers;
 
 int olsrd_plugin_interface_version(void);
 int olsrd_plugin_init(void);
diff --git a/lib/jsoninfo/src/olsrd_plugin.c b/lib/jsoninfo/src/olsrd_plugin.c
index 36550a8..03aa45f 100644
--- a/lib/jsoninfo/src/olsrd_plugin.c
+++ b/lib/jsoninfo/src/olsrd_plugin.c
@@ -64,6 +64,7 @@ union olsr_ip_addr jsoninfo_accept_ip;
 union olsr_ip_addr jsoninfo_listen_ip;
 int ipc_port;
 int nompr;
+bool http_headers;
 
 static void my_init(void) __attribute__ ((constructor));
 static void my_fini(void) __attribute__ ((destructor));
@@ -79,6 +80,7 @@ my_init(void)
 
   /* defaults for parameters */
   ipc_port = 9090;
+  http_headers = false;
   if (olsr_cnf->ip_version == AF_INET) {
     jsoninfo_accept_ip.v4.s_addr = htonl(INADDR_LOOPBACK);
     jsoninfo_listen_ip.v4.s_addr = htonl(INADDR_ANY);
@@ -120,11 +122,26 @@ store_string(const char *value, void *data, set_plugin_parameter_addon addon __a
   return 0;
 }
 
+static int
+store_boolean(const char *value, void *data, set_plugin_parameter_addon addon __attribute__ ((unused)))
+{
+  bool *dest = data;
+  if(strcmp(value, "yes") == 0)
+    *dest = true;
+  else if (strcmp(value, "no") == 0)
+    *dest = false;
+  else
+    return 1; //error
+
+  return 0;
+}
+
 static const struct olsrd_plugin_parameters plugin_parameters[] = {
   {.name = "port",.set_plugin_parameter = &set_plugin_port,.data = &ipc_port},
   {.name = "accept",.set_plugin_parameter = &set_plugin_ipaddress,.data = &jsoninfo_accept_ip},
   {.name = "listen",.set_plugin_parameter = &set_plugin_ipaddress,.data = &jsoninfo_listen_ip},
   {.name = "uuidfile",.set_plugin_parameter = &store_string,.data = uuidfile},
+  {.name = "httpheaders",.set_plugin_parameter = &store_boolean,.data = &http_headers},
 };
 
 void
-- 
1.9.0





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