Add mg_http_var

docs/README.md

@@ -1148,6 +1148,25 @@ if (cookie != NULL) {
 }
 ```
 
+### mg\_http\_var()
+
+```c
+struct mg_str mg_http_var(struct mg_str buf, struct mg_str name);
+```
+
+Fetch an undecoded HTTP variable. Parameters:
+- `buf` - a url-encoded string: HTTP request body or query string
+- `name` - a variable name to fetch
+
+Return value: variable's value. If not found, it it a NULL string.
+
+
+```c
+// We have received a request to /my/uri?a=b&c=d%20
+// The hm->query points to "a=b&c=d%20"
+struct mg_str v = mg_http_var(hm->query, mg_str("c"));  // v = "d%20"
+```
+
 
 ### mg\_http\_get\_var()
 
@@ -1155,7 +1174,7 @@ if (cookie != NULL) {
 int mg_http_get_var(const struct mg_str *var, const char *name, char *buf, int len);
 ```
 
-Decode HTTP variable
+Fetch and decode an HTTP variable
 
 Parameters:
 - `var` - HTTP request body
@@ -1170,6 +1189,8 @@ Usage example:
 ```c
 char buf[100] = "";
 mg_http_get_var(&hm->body, "key1", buf, sizeof(buf)) {
+  ...
+}
 ```
 
 ### mg\_http\_creds()

mongoose.c

@@ -1081,32 +1081,32 @@ void mg_http_bauth(struct mg_connection *c, const char *user,
   }
 }
 
+struct mg_str mg_http_var(struct mg_str buf, struct mg_str name) {
+  struct mg_str k, v, result = mg_str_n(NULL, 0);
+  while (mg_split(&buf, &k, &v, '&')) {
+    if (name.len == k.len && mg_ncasecmp(name.ptr, k.ptr, k.len) == 0) {
+      result = v;
+      break;
+    }
+  }
+  return result;
+}
+
 int mg_http_get_var(const struct mg_str *buf, const char *name, char *dst,
                     size_t dst_len) {
-  const char *p, *e, *s;
-  size_t name_len;
   int len;
-
   if (dst == NULL || dst_len == 0) {
     len = -2;  // Bad destination
   } else if (buf->ptr == NULL || name == NULL || buf->len == 0) {
     len = -1;  // Bad source
     dst[0] = '\0';
   } else {
-    name_len = strlen(name);
+    struct mg_str v = mg_http_var(*buf, mg_str(name));
-    e = buf->ptr + buf->len;
+    if (v.ptr == NULL) {
-    len = -4;  // Name does not exist
+      len = -4;  // Name does not exist
-    dst[0] = '\0';
+    } else {
-    for (p = buf->ptr; p + name_len < e; p++) {
+      len = mg_url_decode(v.ptr, v.len, dst, dst_len, 1);
-      if ((p == buf->ptr || p[-1] == '&') && p[name_len] == '=' &&
+      if (len < 0) len = -3;  // Failed to decode
-          !mg_ncasecmp(name, p, name_len)) {
-        p += name_len + 1;
-        s = (const char *) memchr(p, '&', (size_t) (e - p));
-        if (s == NULL) s = e;
-        len = mg_url_decode(p, (size_t) (s - p), dst, dst_len, 1);
-        if (len < 0) len = -3;  // Failed to decode
-        break;
-      }
     }
   }
   return len;

mongoose.h

@@ -1083,6 +1083,7 @@ void mg_http_serve_file(struct mg_connection *, struct mg_http_message *hm,
 void mg_http_reply(struct mg_connection *, int status_code, const char *headers,
                    const char *body_fmt, ...);
 struct mg_str *mg_http_get_header(struct mg_http_message *, const char *name);
+struct mg_str mg_http_var(struct mg_str buf, struct mg_str name);
 int mg_http_get_var(const struct mg_str *, const char *name, char *, size_t);
 int mg_url_decode(const char *s, size_t n, char *to, size_t to_len, int form);
 size_t mg_url_encode(const char *s, size_t n, char *buf, size_t len);

src/http.c

@@ -87,32 +87,32 @@ void mg_http_bauth(struct mg_connection *c, const char *user,
   }
 }
 
+struct mg_str mg_http_var(struct mg_str buf, struct mg_str name) {
+  struct mg_str k, v, result = mg_str_n(NULL, 0);
+  while (mg_split(&buf, &k, &v, '&')) {
+    if (name.len == k.len && mg_ncasecmp(name.ptr, k.ptr, k.len) == 0) {
+      result = v;
+      break;
+    }
+  }
+  return result;
+}
+
 int mg_http_get_var(const struct mg_str *buf, const char *name, char *dst,
                     size_t dst_len) {
-  const char *p, *e, *s;
-  size_t name_len;
   int len;
-
   if (dst == NULL || dst_len == 0) {
     len = -2;  // Bad destination
   } else if (buf->ptr == NULL || name == NULL || buf->len == 0) {
     len = -1;  // Bad source
     dst[0] = '\0';
   } else {
-    name_len = strlen(name);
+    struct mg_str v = mg_http_var(*buf, mg_str(name));
-    e = buf->ptr + buf->len;
+    if (v.ptr == NULL) {
-    len = -4;  // Name does not exist
+      len = -4;  // Name does not exist
-    dst[0] = '\0';
+    } else {
-    for (p = buf->ptr; p + name_len < e; p++) {
+      len = mg_url_decode(v.ptr, v.len, dst, dst_len, 1);
-      if ((p == buf->ptr || p[-1] == '&') && p[name_len] == '=' &&
+      if (len < 0) len = -3;  // Failed to decode
-          !mg_ncasecmp(name, p, name_len)) {
-        p += name_len + 1;
-        s = (const char *) memchr(p, '&', (size_t) (e - p));
-        if (s == NULL) s = e;
-        len = mg_url_decode(p, (size_t) (s - p), dst, dst_len, 1);
-        if (len < 0) len = -3;  // Failed to decode
-        break;
-      }
     }
   }
   return len;

src/http.h

@@ -53,6 +53,7 @@ void mg_http_serve_file(struct mg_connection *, struct mg_http_message *hm,
 void mg_http_reply(struct mg_connection *, int status_code, const char *headers,
                    const char *body_fmt, ...);
 struct mg_str *mg_http_get_header(struct mg_http_message *, const char *name);
+struct mg_str mg_http_var(struct mg_str buf, struct mg_str name);
 int mg_http_get_var(const struct mg_str *, const char *name, char *, size_t);
 int mg_url_decode(const char *s, size_t n, char *to, size_t to_len, int form);
 size_t mg_url_encode(const char *s, size_t n, char *buf, size_t len);