Update README.md

README.md

@@ -1,5 +1,52 @@
 JWT Implementation for Nim-lang
 ===============================
 
-This is a implementation of JSON Web Tokens for Nim, it allows for certain
-operations to be performed.
+This is a implementation of JSON Web Tokens for Nim, it allows for the following operations to be performed:
+
+`proc toJWT*(node: JsonNode): JWT` - parse a JSON object representing a JWT token to create a JWT token object.
+
+`proc toJWT*(s: string): JWT` - parse a base64 string to decode it to a JWT token object
+
+`sign*(token: var JWT, secret: var string)` - sign a token. Creates a `signature` property on the given token and assigns the signature to it.
+
+`proc verify*(token: JWT, secret: var string): bool` - verify a token (typically on your incoming requests)
+
+`proc $*(token: JWT): string` - creates a b64url string from the token
+
+## Example
+
+An example to demonstrate use with a userId
+
+```
+import jwt, times, json, tables
+
+var secret = "secret"
+
+proc sign*(userId: string): string =
+  var token = toJWT(%*{
+      "header": {
+        "alg": "HS256",
+        "typ": "JWT"
+      },
+      "claims": {
+        "userId": userId,
+        "exp": (getTime() + 1.days).toSeconds().int
+      }
+    })
+
+  token.sign(secret)
+
+  result = $token
+
+proc verify*(token: string): bool =
+  try:
+    let jwtToken = token.toJWT()
+    result = jwtToken.verify(secret)
+  except InvalidToken:
+    result = false
+
+proc decode*(token: string): string =
+  let jwt = token.toJWT()
+  result = $jwt.claims["userId"].node.str
+
+```