From 0f438360accd6a0d2601dc12ce04e65d77e65bb2 Mon Sep 17 00:00:00 2001
From: HansBhatia <78050086+HansBhatia@users.noreply.github.com>
Date: Fri, 23 Jun 2023 15:33:29 -0400
Subject: [PATCH] feat(if-else): add if-else access control (#44)

* feat(if-else): add if-else access control

* fix(if_else): CI issue

* fix: add pr review changes

* fix: pr review comments

* docs: add documentation to contract

* docs(src): add readme file

* docs(src): add contract desc

* fix: terminology & add to SUMMARY

---------

Co-authored-by: msaug <msaug@protonmail.com>
---
 listings/ch00-introduction/if_else/.gitignore |  1 +
 listings/ch00-introduction/if_else/Scarb.toml |  8 ++++
 .../if_else/src/access_log.cairo              | 37 +++++++++++++++++++
 .../ch00-introduction/if_else/src/lib.cairo   |  1 +
 src/SUMMARY.md                                |  1 +
 src/ch00-09-if_statements.md                  | 11 ++++++
 6 files changed, 59 insertions(+)
 create mode 100644 listings/ch00-introduction/if_else/.gitignore
 create mode 100644 listings/ch00-introduction/if_else/Scarb.toml
 create mode 100644 listings/ch00-introduction/if_else/src/access_log.cairo
 create mode 100644 listings/ch00-introduction/if_else/src/lib.cairo
 create mode 100644 src/ch00-09-if_statements.md

diff --git a/listings/ch00-introduction/if_else/.gitignore b/listings/ch00-introduction/if_else/.gitignore
new file mode 100644
index 00000000..eb5a316c
--- /dev/null
+++ b/listings/ch00-introduction/if_else/.gitignore
@@ -0,0 +1 @@
+target
diff --git a/listings/ch00-introduction/if_else/Scarb.toml b/listings/ch00-introduction/if_else/Scarb.toml
new file mode 100644
index 00000000..f0ebf1bd
--- /dev/null
+++ b/listings/ch00-introduction/if_else/Scarb.toml
@@ -0,0 +1,8 @@
+[package]
+name = "if_else"
+version = "0.1.0"
+
+[dependencies]
+starknet = "1.1.0"
+
+[[target.starknet-contract]]
\ No newline at end of file
diff --git a/listings/ch00-introduction/if_else/src/access_log.cairo b/listings/ch00-introduction/if_else/src/access_log.cairo
new file mode 100644
index 00000000..562a64b9
--- /dev/null
+++ b/listings/ch00-introduction/if_else/src/access_log.cairo
@@ -0,0 +1,37 @@
+#[contract]
+mod SimpleAccessLog {
+    // Import the Starknet contract API.
+    use starknet::{get_caller_address, ContractAddress};
+
+    struct Storage {
+        // Add the owner to the contract storage.
+        _owner: ContractAddress,
+    }
+
+    #[event]
+    // Add a welcome event to the contract.
+    fn WelcomeEvent(name: felt252) {}
+
+    #[constructor]
+    fn constructor(address: ContractAddress) {
+        // Set the owner to be the address that deployed the contract.
+        _owner::write(address);
+    }
+
+    // Add a function that checks if the caller is the owner.
+    fn is_owner() -> bool {
+        return get_caller_address() == _owner::read();
+    }
+
+    #[external]
+    fn log_access() {
+        //  Add a conditional event that welcomes the owner or the user.
+        if (is_owner()) {
+            // We know since is_owner() == true, the owner called the function. Call the welcome event with 'Welcome Admin!'.
+            WelcomeEvent('Welcome Admin!');
+        } else {
+            // We know since is_owner() == false, a normal user(not owner) called the function. Call the welcome event with 'Welcome User!'.
+            WelcomeEvent('Welcome User!');
+        }
+    }
+}
diff --git a/listings/ch00-introduction/if_else/src/lib.cairo b/listings/ch00-introduction/if_else/src/lib.cairo
new file mode 100644
index 00000000..527913e1
--- /dev/null
+++ b/listings/ch00-introduction/if_else/src/lib.cairo
@@ -0,0 +1 @@
+mod access_log;
diff --git a/src/SUMMARY.md b/src/SUMMARY.md
index 5969884c..4a363092 100644
--- a/src/SUMMARY.md
+++ b/src/SUMMARY.md
@@ -10,6 +10,7 @@ Summary
   - [Mappings](./ch00-06-mappings.md)
   - [Constructors](./ch00-07-constructor.md)
   - [Function Attributes](./ch00-08-function_attributes.md)
+  - [If statements](./ch00-09-if_statements.md)
 
 - [Applications](./ch01-00-applications.md)
   - [Upgradeable Contract](./ch01-01-upgradeable_contract.md)
diff --git a/src/ch00-09-if_statements.md b/src/ch00-09-if_statements.md
new file mode 100644
index 00000000..f34ac2af
--- /dev/null
+++ b/src/ch00-09-if_statements.md
@@ -0,0 +1,11 @@
+# If Statements
+
+Using an if expression allows you to execute certain code depending on conditions. Within the if statement provide a condition and then specify what you want to execute within the block of code. You can specify an else expression which is reached if the If condition is not met.
+
+Here's a simple example of a contract using if and else statements for role based access log:
+
+The contract will log a welcome message to the console depending on who called the function. If the owner called the function, the welcome message will be 'Welcome Admin!'. If a normal user called the function, the welcome message will be 'Welcome User!'.
+
+```rust
+{{#include ../listings/ch00-introduction/if_else/src/access_log.cairo}}
+```