feat: add http header param getter

include/lnm/common.h

@@ -97,4 +97,16 @@ uint64_t lnm_digits(uint64_t num);
  */
 bool lnm_is_ascii(const char *s);
 
+/**
+ * Find the first case-insensitive occurence of s2 in s1.
+ *
+ * @param s1 pointer to string to look in
+ * @param s1_len length of s1
+ * @param s2 string to search for in s1
+ * @param s2_len length of s2
+ * @return pointer to start of matched string if found, or NULL otherwise
+ */
+const char *lnm_stristr(const char *s1, size_t s1_len, const char *s2,
+                        size_t s2_len);
+
 #endif

include/lnm/http/req.h

@@ -14,7 +14,11 @@
 #define LNM_HTTP_MAX_REQ_HEADERS 32
 #define LNM_HTTP_MAX_REGEX_GROUPS 4
 
-typedef struct lnm_http_req_header {
+/**
+ * Internal representation of a header in a request, defined using offsets
+ * relative to the full buffer.
+ */
+typedef struct lnm_http_req_ihdr {
   struct {
     size_t o;
     size_t len;
@@ -23,7 +27,7 @@ typedef struct lnm_http_req_header {
     size_t o;
     size_t len;
   } value;
-} lnm_http_req_header;
+} lnm_http_req_ihhr;
 
 /**
  * Represents the parsed HTTP request
@@ -46,7 +50,7 @@ typedef struct lnm_http_req {
     size_t len;
   } query;
   struct {
-    lnm_http_req_header arr[LNM_HTTP_MAX_REQ_HEADERS];
+    lnm_http_req_ihhr arr[LNM_HTTP_MAX_REQ_HEADERS];
     size_t len;
   } headers;
   struct {
@@ -82,32 +86,44 @@ lnm_http_parse_err lnm_http_req_parse(lnm_http_req *req, char *buf, size_t len);
 void lnm_http_req_reset(lnm_http_req *req);
 
 /**
- * Retrieve a specific header from the request.
+ * Represents an actual header value, with offsets already resolved.
+ */
+typedef struct lnm_http_req_hdr {
+  struct {
+    const char *s;
+    size_t len;
+  } name;
+  struct {
+    const char *s;
+    size_t len;
+  } value;
+} lnm_http_req_hdr;
+
+/**
+ * Retrieve a known type header from the request.
  *
  * Pointers retrieved from this function should never be used between step
  * functions; simply request the header again if you need to.
  *
- * @param out where to write pointer to header value
- * @param out_len where to store length of out value
+ * @param out where to store pointer to struct representing header
  * @param req request to look for header in
  * @param type type of header to look for
  */
-lnm_err lnm_http_req_header_get(const char **out, size_t *out_len,
-                                lnm_http_req *req, lnm_http_header type);
+lnm_err lnm_http_req_header_get(lnm_http_req_hdr *out, lnm_http_req *req,
+                                lnm_http_header type);
 
 /**
- * Retrieve a specific header from the request by specifying its name.
+ * Retrieve a header from the request using a case-insensitive name.
  *
  * Pointers retrieved from this function should never be used between step
  * functions; simply request the header again if you need to.
  *
- * @param out where to write pointer to header value
- * @param out_len where to store length of out value
+ * @param out where to store pointer to struct representing header
  * @param req request to look for header in
  * @param name name of the header; matches case-insensitive
  */
-lnm_err lnm_http_req_header_get_s(const char **out, size_t *out_len,
-                                  lnm_http_req *req, const char *name);
+lnm_err lnm_http_req_header_get_s(lnm_http_req_hdr *out, lnm_http_req *req,
+                                  const char *name);
 
 /**
  * Retrieve a named key segment from the matched route.
@@ -119,4 +135,18 @@ lnm_err lnm_http_req_header_get_s(const char **out, size_t *out_len,
 size_t lnm_http_req_route_segment(const char **out, lnm_http_req *req,
                                   const char *key);
 
+/**
+ * Retrieve a specific key-value parameter from a header.
+ *
+ * Pointers retrieved from this function should never be used between step
+ * functions; simply request the header again if you need to.
+ *
+ * @param out output struct
+ * @param header header to look in
+ * @param key name of the parameter to return from the header
+ */
+size_t lnm_http_req_header_param(const char **out,
+                                 const lnm_http_req_hdr *header,
+                                 const char *key);
+
 #endif

src/lnm/http/lnm_http_loop_process.c

@@ -79,11 +79,10 @@ void lnm_http_loop_process_parse_headers(lnm_http_conn *conn) {
   lnm_http_loop_ctx *ctx = conn->ctx;
   lnm_http_req *req = &ctx->req;
 
-  const char *value;
-  size_t value_len;
-  if (lnm_http_req_header_get(&value, &value_len, req,
-                              lnm_http_header_content_length) == lnm_err_ok) {
-    req->body.expected_len = lnm_atoi(value, value_len);
+  lnm_http_req_hdr header;
+  if (lnm_http_req_header_get(&header, req, lnm_http_header_content_length) ==
+      lnm_err_ok) {
+    req->body.expected_len = lnm_atoi(header.value.s, header.value.len);
   }
 
   ctx->state = lnm_http_loop_state_steps;

src/lnm/http/lnm_http_loop_steps.c

@@ -30,13 +30,13 @@ lnm_http_step_err lnm_http_loop_step_auth(lnm_http_conn *conn) {
   // If there's no API key, requests are always authorized
   bool authorized = ctx->g->api_key == NULL;
 
-  const char *value;
-  size_t value_len;
+  lnm_http_req_hdr header;
 
-  if (!authorized && lnm_http_req_header_get_s(&value, &value_len, &ctx->req,
+  if (!authorized && lnm_http_req_header_get_s(&header, &ctx->req,
                                                "X-Api-Key") == lnm_err_ok) {
-    authorized = (value_len == strlen(ctx->g->api_key)) &&
-                 (memcmp(value, ctx->g->api_key, value_len) == 0);
+    authorized =
+        (header.value.len == strlen(ctx->g->api_key)) &&
+        (memcmp(header.value.s, ctx->g->api_key, header.value.len) == 0);
   }
 
   ctx->res.status = authorized ? ctx->res.status : lnm_http_status_unauthorized;

src/lnm/http/lnm_http_req.c

@@ -88,23 +88,24 @@ void lnm_http_req_reset(lnm_http_req *req) {
   memset(req, 0, sizeof(lnm_http_req));
 }
 
-lnm_err lnm_http_req_header_get(const char **out, size_t *out_len,
-                                lnm_http_req *req, lnm_http_header type) {
-  return lnm_http_req_header_get_s(out, out_len, req,
-                                   lnm_http_header_names[type]);
+lnm_err lnm_http_req_header_get(lnm_http_req_hdr *out, lnm_http_req *req,
+                                lnm_http_header type) {
+  return lnm_http_req_header_get_s(out, req, lnm_http_header_names[type]);
 }
 
-lnm_err lnm_http_req_header_get_s(const char **out, size_t *out_len,
-                                  lnm_http_req *req, const char *name) {
+lnm_err lnm_http_req_header_get_s(lnm_http_req_hdr *out, lnm_http_req *req,
+                                  const char *name) {
   size_t name_len = strlen(name);
 
   for (size_t i = 0; i < req->headers.len; i++) {
-    const lnm_http_req_header *header = &req->headers.arr[i];
+    const lnm_http_req_ihhr *header = &req->headers.arr[i];
 
     if (lnm_strnieq(req->buf.s + header->name.o, header->name.len, name,
                     name_len)) {
-      *out = req->buf.s + header->value.o;
-      *out_len = header->value.len;
+      out->name.s = req->buf.s + header->name.o;
+      out->name.len = header->name.len;
+      out->value.s = req->buf.s + header->value.o;
+      out->value.len = header->value.len;
 
       return lnm_err_ok;
     }
@@ -128,3 +129,50 @@ size_t lnm_http_req_route_segment(const char **out, lnm_http_req *req,
 
   return segment->len;
 }
+
+size_t lnm_http_req_header_param(const char **out,
+                                 const lnm_http_req_hdr *header,
+                                 const char *key) {
+  size_t key_len = strlen(key);
+  size_t remaining_len = header->value.len;
+
+  // The -1 ensures there's still space for an equals sign after the match
+  const char *s = lnm_stristr(header->value.s, remaining_len - 1, key, key_len);
+
+  // Skip any accidental matches of the key inside another part of the value
+  while (s != NULL && s[key_len] != '=') {
+    remaining_len -= key_len;
+    s = lnm_stristr(s + key_len, remaining_len - 1, key, key_len);
+  };
+
+  // Edge case where empty value is at the end of the string
+  if (s == NULL || s + 2 == header->value.s + header->value.len) {
+    return 0;
+  }
+
+  *out = s + 2;
+  const char *value_end = s + 2;
+
+  // Handle a quoted string
+  if (**out == '"') {
+    value_end++;
+    while (value_end < header->value.s + header->value.len &&
+           (*value_end != '"')) {
+      value_end++;
+    }
+
+    // If we found a matching quote we trim the quotes, otherwise the quote is
+    // part of the value
+    if (value_end < header->value.s + header->value.len) {
+      // We skip the initial quote
+      (*out)++;
+    }
+  } else {
+    while (value_end < header->value.s + header->value.len &&
+           (*value_end != ',') && (*value_end != ';')) {
+      value_end++;
+    }
+  }
+
+  return value_end - *out;
+}

src/lnm/lnm_utils.c

@@ -67,3 +67,17 @@ bool lnm_is_ascii(const char *s) {
 
   return valid;
 }
+
+const char *lnm_stristr(const char *s1, size_t s1_len, const char *s2,
+                        size_t s2_len) {
+  while (s1_len >= s2_len) {
+    if (lnm_strnieq(s1, s1_len, s2, s2_len)) {
+      return s1;
+    }
+
+    s1_len--;
+    s1++;
+  }
+
+  return NULL;
+}