Add hello world example

CMakeLists.txt

@@ -1,4 +1,5 @@
 cmake_minimum_required(VERSION 3.13.5)
+option(BUILD_EXAMPLES ON)
 project(slweb C)
 add_library(${PROJECT_NAME}
     handler.c
@@ -9,3 +10,7 @@ add_library(${PROJECT_NAME}
 add_subdirectory(dynstr)
 target_include_directories(${PROJECT_NAME} PUBLIC include)
 target_link_libraries(${PROJECT_NAME} PUBLIC dynstr)
+
+if(BUILD_EXAMPLES)
+    add_subdirectory(examples)
+endif()

Makefile

@@ -16,6 +16,12 @@ all: $(PROJECT)
 
 clean:
 	rm -f $(OBJECTS) $(DEPS)
+	+cd examples && $(MAKE) clean
+
+FORCE:
+
+examples: FORCE
+	+cd examples && $(MAKE)
 
 $(PROJECT): $(OBJECTS)
 	$(AR) $(ARFLAGS) $@ $(OBJECTS)

README.md

@@ -103,6 +103,25 @@ add_subdirectory(slweb)
 target_link_libraries(${PROJECT_NAME} PRIVATE slweb)
 ```
 
+### Examples
+
+[A directory](examples) with examples shows how `slweb` can be used by
+applications. These can be built from the top-level directory with:
+
+```sh
+$ make examples
+```
+
+In the case of CMake builds, examples are built by default. This can be turned
+off by assigning `BUILD_EXAMPLES` to `OFF` or `0`:
+
+```sh
+$ mkdir build/
+$ cd build/
+$ cmake .. -DBUILD_EXAMPLES=OFF
+$ cmake --build .
+```
+
 ## Why this project?
 
 Originally, `slweb` was part of the

examples/CMakeLists.txt

@@ -0,0 +1,2 @@
+cmake_minimum_required(VERSION 3.13)
+add_subdirectory(hello)

examples/Makefile

@@ -0,0 +1,11 @@
+.POSIX:
+
+all: hello
+
+clean:
+	+cd hello && $(MAKE) clean
+
+FORCE:
+
+hello: FORCE
+	+cd hello && $(MAKE)

examples/hello/CMakeLists.txt

@@ -0,0 +1,4 @@
+cmake_minimum_required(VERSION 3.13)
+project(hello C)
+add_executable(hello main.c)
+target_link_libraries(${PROJECT_NAME} PRIVATE slweb dynstr)

examples/hello/Makefile

@@ -0,0 +1,26 @@
+.POSIX:
+
+PROJECT = hello
+DEPS = \
+	main.o
+SLWEB = ../../libslweb.a
+DYNSTR = ../../dynstr/libdynstr.a
+CFLAGS = -I ../../include -I ../../dynstr/include
+SLWEB_FLAGS = -L ../../ -l slweb
+DYNSTR_FLAGS = -L ../../dynstr -l dynstr
+
+all: $(PROJECT)
+
+clean:
+	rm -f $(DEPS)
+
+FORCE:
+
+$(PROJECT): $(DEPS) $(SLWEB) $(DYNSTR)
+	$(CC) $(LDFLAGS) $(DEPS) $(SLWEB_FLAGS) $(DYNSTR_FLAGS) -o $@
+
+$(SLWEB): FORCE
+	+cd ../../ && $(MAKE)
+
+$(DYNSTR): FORCE
+	+cd ../../dynstr && $(MAKE)

examples/hello/README.md

@@ -0,0 +1,17 @@
+# "Hello world" example
+
+This example shows a minimal setup for an application using `slweb`. When
+executed, it starts a HTTP/1.1 server on port `8080` and returns an example
+website reading "Hello from slweb!" when either `/` or `/index.html` are
+accessed by clients.
+
+## How to build
+
+If using `make(1)`, just run `make` from this directory.
+
+If using CMake, examples are built by default when configuring the project
+from [the top-level `CMakeLists.txt`](../../CMakeLists.txt).
+
+## How to run
+
+Run the executable without any command line arguments.

examples/hello/main.c

@@ -0,0 +1,101 @@
+#include <dynstr.h>
+#include <slweb/handler.h>
+#include <slweb/html.h>
+#include <slweb/http.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+static int hello(const struct http_payload *const pl,
+    struct http_response *const r, void *const user)
+{
+    int ret = -1;
+    struct html_node *html = html_node_alloc("html"), *body, *p;
+    struct dynstr d;
+
+    dynstr_init(&d);
+
+    if (!html)
+    {
+        fprintf(stderr, "%s: html_node_alloc failed\n", __func__);
+        goto end;
+    }
+    else if (!(body = html_node_add_child(html, "body")))
+    {
+        fprintf(stderr, "%s: html_node_add_child body failed\n", __func__);
+        goto end;
+    }
+    else if (!(p = html_node_add_child(html, "p")))
+    {
+        fprintf(stderr, "%s: html_node_add_child p failed\n", __func__);
+        goto end;
+    }
+    else if (html_node_set_value(p, "Hello from slweb!"))
+    {
+        fprintf(stderr, "%s: html_node_set_value p failed\n", __func__);
+        goto end;
+    }
+    else if (html_serialize(html, &d))
+    {
+        fprintf(stderr, "%s: html_serialize failed\n", __func__);
+        goto end;
+    }
+
+    *r = (const struct http_response)
+    {
+        .status = HTTP_STATUS_OK,
+        .buf.rw = d.str,
+        .n = d.len,
+        .free = free
+    };
+
+    if (http_response_add_header(r, "Content-Type", "text/html"))
+    {
+        fprintf(stderr, "%s: http_response_add_header failed\n", __func__);
+        goto end;
+    }
+
+    ret = 0;
+
+end:
+    html_node_free(html);
+
+    if (ret)
+        dynstr_free(&d);
+
+    return ret;
+}
+
+int main(int argc, char *argv[])
+{
+    int ret = EXIT_FAILURE;
+    const short port = 8080;
+    const struct handler_cfg cfg = {0};
+    struct handler *const h = handler_alloc(&cfg);
+    static const char *const urls[] = {"/", "/index.html"};
+
+    if (!h)
+    {
+        fprintf(stderr, "%s: handler_alloc failed\n", __func__);
+        goto end;
+    }
+
+    for (size_t i = 0; i < sizeof urls / sizeof *urls; i++)
+        if (handler_add(h, urls[i], HTTP_OP_GET, hello, NULL))
+        {
+            fprintf(stderr, "%s: handler_add failed\n", __func__);
+            goto end;
+        }
+
+    if (handler_listen(h, port))
+    {
+        fprintf(stderr, "%s: handler_listen failed\n", __func__);
+        goto end;
+    }
+
+    ret = EXIT_SUCCESS;
+
+end:
+    handler_free(h);
+    return ret;
+}