Handling Requests

We can easily access the request’s body, params, query, and headers. We’ll see just basic examples in this chapter.

Let’s see how it basically works.

Request Body

src/handlers.h

#ifndef HANDLERS_H
#define HANDLERS_H

#include "ecewo.h"

void print_body(Req *req, Res *res);

#endif

src/handlers.c

#include "handlers.h"

void print_body(Req *req, Res *res)
{
    printf("Body: %s\n", req->body);
    send_text(200, "Success!");
}

src/main.c

#include "server.h"
#include "handlers.h"   // "ecewo.h" already comes from here

int main()
{
    init_router();
    post("/print-body", print_body);
    ecewo(3000);
    reset_router();
    return 0;
}

Let’s send a POST request to the http://localhost:3000/print-body with this body:

{
    "name": "John",
    "surname": "Doe",
    "username": "johndoe"
}

We’ll receive a Success message and see the body in the console:

Body: {
    "name": "John",
    "surname": "Doe",
    "username": "johndoe"
}

For more advanced usage; see Using JSON chapter.

Request Params

Let’s take a specific user by params. We can access the params using the get_params("slug"); API. Let’s write a handler that gives us the “slug”:

src/handlers.h

#ifndef HANDLERS_H
#define HANDLERS_H

#include "ecewo.h"

void send_params(Req *req, Res *res);

#endif

src/handlers.c

#include "handlers.h"

void send_params(Req *req, Res *res)
{
    const char *slug = get_params("slug"); // We got the params

    if (slug == NULL)
    {
        send_text(400, "Missing 'slug' parameter");
        return;
    }

    send_text(200, slug);
}

src/main.c

#include "server.h"
#include "handlers.h"

int main()
{
    init_router();
    get("/send-params/:slug", send_params);
    ecewo(3000);
    reset_router();
    return 0;
}

Recompile the program and send a request to http://localhost:3000/send-params/testslug. Server will send us testslug response.

We can define more than one slug if we need using the same way. Here is an example:

src/main.c

#include "server.h"
#include "handlers.h"

int main()
{
    init_router();
    get("/print-more-params/:key/and/:value");
    ecewo(3000);
    reset_router();
    return 0;
}

src/handlers.h

#ifndef HANDLERS_H
#define HANDLERS_H

#include "ecewo.h"

void print_more_params(Req *req, Res *res);

#endif

src/handlers.c

#include "handlers.h"

void print_more_params(Req *req, Res *res)
{
    const char *key = get_params("key");        // We got the /:key
    const char *value = get_params("value");    // We got the /:value

    if (key == NULL || value == NULL)
    {
        send_text(400, "Missing 'key' or 'value' parameter");
        return;
    }

    printf("Key slug: %s Value slug: %s\n", key, value);

    send_text(200, "Success!");
}

If we go to http://localhost:3000/print-more-params/foo/and/bar path, we’ll receive a Success! response and see the foo and bar in the console:

Key slug: foo Value slug: bar

Request Query

Just like the params, we can use get_query("query"); to get the query params. Let’s rewrite a handler using query:

src/main.c

#include "server.h"
#include "handlers.h"

int main()
{
    init_router();
    get("/print-query", print_query);
    ecewo(3000);
    reset_router();
    return 0;
}

src/handlers.h

#ifndef HANDLERS_H
#define HANDLERS_H

#include "ecewo.h"

void print_query(Req *req, Res *res);

#endif

src/handlers.c

#include "ecewo.h"

void print_query(Req *req, Res *res)
{
    const char *name = get_query("name");
    const char *surname = get_query("surname");

    if (name == NULL || surname == NULL)
    {
        send_text(400, "Missing required parameter.");
        return;
    }

    printf("Name: %s Surname: %s\n", name, surname);

    send_text(200, "Success!");
}

Let’s recompile the program and send a request to http://localhost:3000/print-query?name=john&surname=doe. We’ll receive a Success! responseand the query strings will be printed in the console:

Name: john Surname: doe

Request Headers

Just like params and query, we can also access request headers using the get_headers("header"); API. Ecewo also provides different APIs for authorization and session-based authentication. However, if you simply want to access a specific item in req->headers, you can do so directly.

Typically, a standard GET request with POSTMAN have some headers like:

{
    "User-Agent": "PostmanRuntime/7.43.3",
    "Accept": "*/*",
    "Postman-Token": "9b1c7dda-27f9-471a-9cdd-bfaf0d5b56a1",
    "Host": "localhost:3000",
    "Accept-Encoding": "gzip, deflate, br",
    "Connection": "keep-alive"
}

Let’s say, we need the User-Agent header:

src/handlers.h

#ifndef HANDLERS_H
#define HANDLERS_H

#include "ecewo.h"

void get_user_agent(Req *req, Res *res);

#endif

src/handlers.c

#include "handlers.h"

void get_user_agent(Req *req, Res *res)
{
    const char *user_agent = get_headers("User-Agent");

    if (user_agent == NULL)
    {
        send_text(400, "Missing required parameter.");
        return;
    }

    send_text(200, user_agent);
}

src/main.c

#include "server.h"
#include "handlers.h"

int main()
{
    init_router();
    get("/header", get_user_agent);
    ecewo(3000);
    reset_router();
    return 0;
}

The result will be something like this:

    User Agent: PostmanRuntime/7.43.3