add validator library

Author: ashtonjamesd

doc/api/errors.md

@@ -2,8 +2,23 @@
 
 You have the freedom to handle errors however you like. However, Lavandula provides a interface for returning JSON errors from your controllers.
 
+Errors returned from Lavandula have two fields, a `success` boolean and a `message` string.
 
+Currently, to return an error from the 
+```
+return apiResponse("missing body in request");
+```
+
+This is a method commonly used in middleware. The point of it is to refrain from returning plain text error messages as JSON is easier to work with and standardise.
+
+Here is an example of this used in some middleware.
 
 ```
+middleware(validateJsonBody, ctx, m) {
+    if (!ctx.hasBody) {
+        return apiResponse("Error: no JSON body provided.");
+    }
 
+    return next(ctx, m);
+}
 ```

doc/api/middleware.md

@@ -64,3 +64,22 @@ HttpResponse myMiddleware(RequestContext ctx, MiddlewareHandler *middleware) {
 
 ## Library Middleware
 
+Lavandula provides some common middleware functions to use in your application.
+
+### Console Logger
+
+The logger middleware logs the method and route every time the web server is hit. This is useful for debugging purposes.
+
+```c
+AppBuilder builder = createBuilder();
+useGlobalMiddleware(&builder, consoleLogger);
+```
+
+### JSON Body Validator
+
+The JSON body middleware validates the presence of a JSON body. A bad request will be returned otherwise.
+
+```c
+Route rootRoute = root(&app, home);
+useLocalMiddleware(&rootRoute, validateJsonBody);
+```

doc/api/request_context.md

@@ -0,0 +1,20 @@
+# Request Context
+
+The request context is the second argument passed into an `appRoute`. It holds data and resources related to the request routed to this controller endpoint. It also contains the instance of your `App`.
+
+Because calling `jsonParse` on the `request.body` is a very common operation, this is done for you and stored as a field in the `RequestContext`. If the body is not present, you can null check the `body` field itself, or use the boolean `hasBody` field.
+
+```c
+appRoute(home, ctx) {
+    if (!ctx.hasBody) {
+        return internalServerError("No body!", TEXT_PLAIN);
+    }
+
+    // return the request body for this example
+    char *body = jsonStringify(ctx.body);
+
+    return ok(body, TEXT_PLAIN);
+}
+```
+
+Do not call `freeJsonBuilder` on the ctx.body as this is done for you once the request returns a response. Don't worry if you forget as it will not crash your program.

doc/api/validator.md

@@ -0,0 +1,33 @@
+# JSON Validation
+
+Lavandula provides a JSON validator interface for ensuring the correct data is being sent to your application.
+
+Start by creating a validator instance. Then you can call various methods to add rules to the validator. The example below calls the `required` method to add expected fields in the JSON body.
+
+Then, call `validate` to check the context body against the previously defined rules. It will return `NULL` if there is no error. Lastly, free the validator instance to clean up resources.
+
+```c
+middleware(registerUserValidator, ctx, m) {
+    JsonValidator v = createValidator();
+
+    required(&v, "username");
+    required(&v, "password");
+
+    char *error = validate(&v, ctx.body);
+    if (error) {
+        return apiResponse(error);
+    }
+    freeValidator(&v);
+
+    return next(ctx, m);
+}
+```
+
+The JSON validator provides automatic validation against the presence of a body. If a body is not present and a validator is used then the following response will be returned.
+
+```json
+{
+    "success": false,
+    "message": "Request body is missing or malformed."
+}
+```

doc/sql.md

@@ -1,7 +1,5 @@
 # Lavandula with SQL
 
-This file assumes you have a linux-based environment.
-
 
 
 ## Setting up SqlLite3

examples/all.c examples/basic/all.cexamples/all.c renamed to examples/basic/all.c

@@ -1,12 +1,12 @@
-#include "lavandula.h"
-
-appRoute(home, ctx) {
-    return ok("Hello, World", TEXT_PLAIN);
-}
-
-int main() {
-    App app = createApp();
-    root(&app, home);
-
-    runApp(&app);
+#include "lavandula.h"
+
+appRoute(home, ctx) {
+    return ok("Hello, World", TEXT_PLAIN);
+}
+
+int main() {
+    App app = createApp();
+    root(&app, home);
+
+    runApp(&app);
 }

examples/basic.c examples/basic/basic.cexamples/basic.c renamed to examples/basic/basic.c

@@ -1,23 +1,23 @@
-#include "../src/include/lavandula.h"
-
-#include "include/lavandula.h"
-
-appRoute(home, ctx) {
-    return ok("Hello, World!", TEXT_PLAIN);
-}
-
-int main(int argc, char *argv[]) {
-    AppBuilder builder = createBuilder();
-
-    // add basic auth into the global middleware pipeline (for all endpoints)
-    useBasicAuth(&builder);
-
-    App app = build(builder);
-
-    // add some sample credentials
-    addBasicCredentials(&app.auth, "admin", "password");
-
-    get(&app, "/home", home);
-
-    runApp(&app);
+#include "../src/include/lavandula.h"
+
+#include "include/lavandula.h"
+
+appRoute(home, ctx) {
+    return ok("Hello, World!", TEXT_PLAIN);
+}
+
+int main(int argc, char *argv[]) {
+    AppBuilder builder = createBuilder();
+
+    // add basic auth into the global middleware pipeline (for all endpoints)
+    useBasicAuth(&builder);
+
+    App app = build(builder);
+
+    // add some sample credentials
+    addBasicCredentials(&app.auth, "admin", "password");
+
+    get(&app, "/home", home);
+
+    runApp(&app);
 }