Request

conn.host         #=> "example.com"
conn.method       #=> "GET"
conn.path_info    #=> ["posts", "1"]
conn.request_path #=> "/posts/1"
conn.query_string #=> "utm_source=twitter"
conn.port         #=> 80
conn.scheme       #=> :http
conn.peer         #=> { {127, 0, 0, 1}, 12345 }
conn.remote_ip    #=> { 151, 236, 219, 228 }
conn.req_headers  #=> [{"content-type", "text/plain"}]
conn |> get_req_header("referrer")

Updating

Usually only useful for tests.

conn
|> put_req_header("accept", "application/json")

Response

conn.resp_body    #=> "..."
conn.resp_charset #=> "utf-8"
conn.resp_cookies #=> ...
conn.resp_headers #=> ...
conn.status       #=> ...

Sending responses

# Plug.Conn
conn
|> html("<html><head>...")
|> json(%{ message: "Hello" })
|> text("Hello")

|> redirect(to: "/foo")
|> redirect(external: "http://www.google.com/")
|> halt()

|> put_resp_content_type("text/plain")
|> put_resp_cookie("abc", "def")
|> put_resp_header("X-Delivered-By", "myapp")
|> put_status(202)
|> put_status(:not_found)

|> put_private(:plug_foo, "...")  # reserved for libraries

|> send_resp(201, "")

Phoenix views

# Phoenix.Controller
conn
|> render("index.html")
|> render("index.html", hello: "world")
|> render(MyApp.ErrorView, "404.html")

|> put_layout(:foo)
|> put_layout(false)
|> put_view(ErrorView)
|> put_secure_browser_headers()
# prevent clickjacking, nosniff, and xss protection
# x-frame-options, x-content-type-options, x-xss-protection

|> put_new_view(ErrorView)  # if not set yet
|> put_new_layout(:foo)
layout(conn)

Accepts

plug :accepts, ["html", "json"]
conn |> accepts(["html", "json"])
get_format(conn)  #=> "html"
conn.accepts

Misc

conn.assigns         # storage of crap
conn.owner           # process
conn.halted          # if pipeline was halted
conn.secret_key_base # ...
conn.state           # :unset, :set, :file, :sent, :chunked

Assigns

conn.assigns[:hello]
conn |> assign(:user_id, 100)
conn = async_assign(conn, :location, fn -> geoip_lookup() end)
await_assign(conn, :location)

Session

conn = fetch_session(conn)   # or plug :fetch_session

conn = put_session(conn, :message, "new stuff we just set in the session")
get_session(conn, :message)
conn = clear_session(conn)

Also: flash cookie params

conn
|> put_flash(:info, "Success")
|> put_flash(:error, "Oh no")