Add parsing query parameters

.gitignore

@@ -1,3 +1,4 @@
 src/*.o
 *.o
 .cache/
+*swp*

include/Parameters.h

@@ -0,0 +1,76 @@
+#ifndef PARAMETERS_H
+#define PARAMETERS_H
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+
+/*
+ * Implementation notes: (22 Jan 2023)
+ *
+ * Parameters will be stored as an array sorted on-demand.
+ * If calling paramGet and it's unsorted, it will sort automatically.
+ * If calling paramGet and it's already sorted, it doesn't touch it.
+ * Adding a new parameter will toggle the is_sorted to false.
+ *
+ * I was considering using the tree implementation of Route but I think
+ * it would make more sense to move the logic into its own data structure
+ * that can be used across different components (like Route & Parameter)
+ * because otherwise it would be confusing if we had a Route struct inside
+ * of a Parameter. For now, I'll use this array structure.
+ *
+ */
+
+struct Parameter
+{
+	char* key;
+	char* value;
+};
+
+struct ParameterArray
+{
+	struct Parameter * parameters;
+	bool is_sorted;
+	size_t n_members;
+	size_t capacity;
+};
+
+// Initialise array of parameters with capacity.
+// Returns pointer to array on success, NULL on failure
+struct ParameterArray * paramInit(const size_t capacity);
+
+// Parse parameters from a string (e.g., when receiving ROUTE url).
+// Takes an existing Parameter pointer and adds new parameters parsed from string.
+// This will MODIFY the url inplace to remove all the parameter text before it's passed
+// on to render a static template.
+void paramParse(
+		struct ParameterArray * params, 
+		char* url);
+
+// Clear all keys & values and set n_members back to zero.
+// This allows us to reuse the struct for multiple requests.
+void paramClear(struct ParameterArray * params);
+
+// Add new parameter to parameter array.
+// Returns true on success and false on failure (e.g., memory allocation)
+bool paramAdd(
+		struct ParameterArray * params,
+		const char* key,
+		const char* value);
+
+// Sort parameters by keys ascending. This is primarily used internally
+// but can be used externally if needed for whatever reason.
+void paramSort(struct ParameterArray * params);
+
+// Return a pointer to a parameter with a given key.
+// Any modifications done will be reflected in parameter array.
+struct Parameter * paramGet(
+		struct ParameterArray * params,
+		const char* key);
+
+// Free all memory consumed by parameters
+void paramFree(struct ParameterArray * params);
+
+#endif

src/Parameters.c

@@ -0,0 +1,175 @@
+#include "Parameters.h"
+
+static void _print_critical()
+{
+	printf("============ CRITICAL ============\n");
+	printf("Memory could not be allocated for parameters.\n");
+}
+
+struct ParameterArray * paramInit(const size_t capacity)
+{
+	struct ParameterArray * params = malloc(sizeof(struct ParameterArray));
+
+	if (!params)
+	{
+		_print_critical();
+		return NULL;
+	}
+
+	params->parameters = calloc(capacity, sizeof(struct Parameter));
+
+	if (!params->parameters)
+	{
+		_print_critical();
+		return NULL;
+	}
+
+	params->is_sorted = false;
+	params->n_members = 0;
+	params->capacity = capacity;
+
+	for (size_t i = 0; i < capacity; ++i)
+	{
+		params->parameters[i].key = NULL;
+		params->parameters[i].value = NULL;
+	}
+
+	return params;
+}
+
+bool paramAdd(
+		struct ParameterArray * params,
+		const char* key,
+		const char* value)
+{
+	const size_t i = params->n_members;
+
+	params->parameters[i].key = strdup(key);
+	params->parameters[i].value = strdup(value);
+
+	params->is_sorted = false;
+	params->n_members++;
+
+	// follow doubling rule
+	if (params->n_members == params->capacity)
+	{
+		void* alloc = realloc(params->parameters, params->capacity * 2 * sizeof(struct Parameter));
+		if (!alloc)
+		{
+			_print_critical();
+			return false;
+		}
+
+		params->capacity *= 2;
+		params->parameters = alloc;
+	}
+
+	return true;
+}
+
+static int key_cmp(const void* a, const void* b)
+{
+	const struct Parameter * _a = a;
+	const struct Parameter * _b = b;
+
+	return strcmp(_a->key, _b->key);
+}
+
+void paramSort(struct ParameterArray * params)
+{
+	qsort(params->parameters, params->n_members, sizeof(struct Parameter), &key_cmp);
+	params->is_sorted = true;
+}
+
+struct Parameter * paramGet(
+		struct ParameterArray * params,
+		const char* key)
+{
+	if (!params->is_sorted)
+		paramSort(params);
+
+	struct Parameter search_key;
+	search_key.key = (char*)key; // try to silent warning about losing const-ness
+
+	return bsearch(&search_key, params->parameters, params->n_members, sizeof(struct Parameter), &key_cmp);
+
+}
+
+void paramParse(
+		struct ParameterArray * params,
+		char* url)
+{
+	char* url_copy = strdup(url);
+	memset(url, 0, strlen(url));
+
+	// temporary large buffers to record the key/values before passing
+	// them to paramAdd
+	char key[1024] = {0};
+	char value[1024] = {0};
+
+	/*
+	 * Parsing Rule:
+	 * k = keys
+	 * v = values
+	 */
+	char parsing_rule = 0;
+
+	for (size_t i = 0; i < strlen(url_copy); ++i)
+	{
+		switch (url_copy[i])
+		{
+			case '?':
+				parsing_rule = 'k';
+				continue;
+			case '=':
+				parsing_rule = 'v';
+				continue;
+			case '&':
+				paramAdd(params, key, value);
+				memset(key, 0, 1024);
+				memset(value, 0, 1024);
+				parsing_rule = 'k';
+				continue;
+			default:
+				if (parsing_rule == 0)
+					strncat(url, &url_copy[i], 1);
+				break;
+		}
+
+		switch (parsing_rule)
+		{
+			case 'k':
+				strncat(key, &url_copy[i], 1);
+				break;
+			case 'v':
+				strncat(value, &url_copy[i], 1);
+				break;
+		}
+	}
+
+	paramAdd(params, key, value);
+	free(url_copy);
+}
+
+void paramClear(struct ParameterArray * params)
+{
+	for (size_t i = 0; i < params->n_members; ++i)
+	{
+		free(params->parameters[i].key);
+		params->parameters[i].key = NULL;
+
+		free(params->parameters[i].value);
+		params->parameters[i].value = NULL;
+	}
+
+	params->n_members = 0;
+}
+
+void paramFree(struct ParameterArray * params)
+{
+	paramClear(params);
+	free(params->parameters);
+	params->parameters = NULL;
+	free(params);
+	params = NULL;
+}

src/main.c

@@ -11,6 +11,7 @@
 #include "HTTP_Server.h"
 #include "Routes.h"
 #include "Response.h"
+#include "Parameters.h"
 
 int main() {
 	// initiate HTTP_Server
@@ -23,9 +24,12 @@ int main() {
 	struct Route * route = initRoute("/", "index.html"); 
 	addRoute(route, "/about", "about.html");
 
+	// create dynamic parameters array
+	struct ParameterArray * params = paramInit(10);
+
 
 	printf("\n====================================\n");
-	printf("=========ALL VAILABLE ROUTES========\n");
+	printf("=========ALL AVAILABLE ROUTES========\n");
 	// display all available routes
 	inorder(route);
 
@@ -64,6 +68,21 @@ int main() {
 		printf("The method is %s\n", method);
 		printf("The route is %s\n", urlRoute);
 
+		if (strlen(urlRoute) > 0)
+		{
+			paramParse(params, urlRoute);
+
+			printf("*** PARSED PARAMETERS ***\n");
+			for (size_t i = 0; i < params->n_members; ++i)
+			{
+				printf("KEY: %s\n", params->parameters[i].key);
+				printf("VALUE: %s\n\n", params->parameters[i].value);
+			}
+			// do something with parameters and can clear them to re-use for the next
+			// request
+			paramClear(params);
+		}
+
 
 		char template[100] = "";
 

test/Makefile

@@ -0,0 +1,4 @@
+# this is not a general makefile but something quick and dirty so I can actually run the debugger
+# (I suck at raw makefiles, too much time using CMake that I'm out of touch :L)
+all:
+	gcc -g -O0 param_parser.c ../src/Parameters.c -I../include -o param_parser 

test/param_parser.c

@@ -0,0 +1,41 @@
+#include "Parameters.h"
+
+/*
+ * Just testing the functionality locally so I don't have to
+ * keep running/killing the server over and over.
+ *
+ * These could be converted to "proper" tests but for now
+ * they are purely visual.
+ */
+int main()
+{
+	char* url = strdup("/someNested/route?name=Zach&val=100&jimmy=John");
+	struct ParameterArray * params = paramInit(10);
+	paramParse(params, url);
+	printf("PARSED PARAMS:\n\n");
+	for (size_t i = 0; i < params->n_members; ++i)
+	{
+		printf("KEY: %s\n", params->parameters[i].key);
+		printf("VALUE: %s\n\n", params->parameters[i].value);
+	}
+	printf("CLEANED URL: %s\n\n", url);
+
+	struct Parameter* search = NULL;
+
+	printf("SEARCH KEY: name\n");
+	search = paramGet(params, "name");
+	printf("FOUND VALUE: %s\n\n", search->value);
+
+	printf("SEARCH KEY: val\n");
+	search = paramGet(params, "val");
+	printf("FOUND VALUE: %s\n\n", search->value);
+
+	printf("SEARCH KEY: xyz\n");
+	search = paramGet(params, "xyz");
+	if (!search)
+		printf("KEY DOESN'T EXIST\n\n");
+
+	paramFree(params);
+	free(url);
+	return 0;
+}