Code Whisper
@codewhisper.bsky.social
👾 Anonymous engineer, sharing thoughts on code, tech & systems.
🚫 No face, just logic.
x.com/codewhisperdev
🚫 No face, just logic.
x.com/codewhisperdev
REST Tip – Use HATEOAS to guide the client
HATEOAS = Hypermedia as the Engine of Application State
📦 Instead of sending just data, include actions
🧠 Why?
• Makes APIs discoverable
• Reduces hard-coded logic on the client
• Enables better versioning and evolution
HATEOAS = Hypermedia as the Engine of Application State
📦 Instead of sending just data, include actions
🧠 Why?
• Makes APIs discoverable
• Reduces hard-coded logic on the client
• Enables better versioning and evolution
April 9, 2025 at 10:21 AM
REST Tip – Use HATEOAS to guide the client
HATEOAS = Hypermedia as the Engine of Application State
📦 Instead of sending just data, include actions
🧠 Why?
• Makes APIs discoverable
• Reduces hard-coded logic on the client
• Enables better versioning and evolution
HATEOAS = Hypermedia as the Engine of Application State
📦 Instead of sending just data, include actions
🧠 Why?
• Makes APIs discoverable
• Reduces hard-coded logic on the client
• Enables better versioning and evolution
6. Nested Classes
Class inside another class.
Can be used for tight coupling (e.g., helper classes for outer class).
Class inside another class.
Can be used for tight coupling (e.g., helper classes for outer class).
April 8, 2025 at 7:14 PM
6. Nested Classes
Class inside another class.
Can be used for tight coupling (e.g., helper classes for outer class).
Class inside another class.
Can be used for tight coupling (e.g., helper classes for outer class).
5. Partial Classes
Split one class across multiple files.
Great for large codebases or designer-generated code.
Split one class across multiple files.
Great for large codebases or designer-generated code.
April 8, 2025 at 7:14 PM
5. Partial Classes
Split one class across multiple files.
Great for large codebases or designer-generated code.
Split one class across multiple files.
Great for large codebases or designer-generated code.
4. Sealed Classes
Can’t be inherited.
Used when you want to restrict extension.
Can’t be inherited.
Used when you want to restrict extension.
April 8, 2025 at 7:14 PM
4. Sealed Classes
Can’t be inherited.
Used when you want to restrict extension.
Can’t be inherited.
Used when you want to restrict extension.
3. Static Classes
Only contains static members. Can’t be instantiated or inherited.
Perfect for utility/helper methods.
Only contains static members. Can’t be instantiated or inherited.
Perfect for utility/helper methods.
April 8, 2025 at 7:14 PM
3. Static Classes
Only contains static members. Can’t be instantiated or inherited.
Perfect for utility/helper methods.
Only contains static members. Can’t be instantiated or inherited.
Perfect for utility/helper methods.
2. Abstract Classes
Use abstract when the class is meant to be inherited, not instantiated.
It can have both abstract (unimplemented) and concrete (implemented) methods.
Use abstract when the class is meant to be inherited, not instantiated.
It can have both abstract (unimplemented) and concrete (implemented) methods.
April 8, 2025 at 7:14 PM
2. Abstract Classes
Use abstract when the class is meant to be inherited, not instantiated.
It can have both abstract (unimplemented) and concrete (implemented) methods.
Use abstract when the class is meant to be inherited, not instantiated.
It can have both abstract (unimplemented) and concrete (implemented) methods.
1. Regular Classes
The most common type: public class MyClass { }
Supports inheritance, encapsulation, constructors, methods, fields.
Can be instantiated with new.
The most common type: public class MyClass { }
Supports inheritance, encapsulation, constructors, methods, fields.
Can be instantiated with new.
April 8, 2025 at 7:14 PM
1. Regular Classes
The most common type: public class MyClass { }
Supports inheritance, encapsulation, constructors, methods, fields.
Can be instantiated with new.
The most common type: public class MyClass { }
Supports inheritance, encapsulation, constructors, methods, fields.
Can be instantiated with new.
HTTP Tip
Idempotent methods can be safely retried without causing side effects.
🔹 GET, PUT, DELETE, HEAD, OPTIONS → Idempotent
🔹 POST → NOT idempotent
🧠 Why?
Using the correct method:
▪️ Makes APIs predictable
▪️ Enables retries in network failures
▪️ Helps with caching, monitoring, and debugging
Idempotent methods can be safely retried without causing side effects.
🔹 GET, PUT, DELETE, HEAD, OPTIONS → Idempotent
🔹 POST → NOT idempotent
🧠 Why?
Using the correct method:
▪️ Makes APIs predictable
▪️ Enables retries in network failures
▪️ Helps with caching, monitoring, and debugging
April 8, 2025 at 5:09 PM
HTTP Tip
Idempotent methods can be safely retried without causing side effects.
🔹 GET, PUT, DELETE, HEAD, OPTIONS → Idempotent
🔹 POST → NOT idempotent
🧠 Why?
Using the correct method:
▪️ Makes APIs predictable
▪️ Enables retries in network failures
▪️ Helps with caching, monitoring, and debugging
Idempotent methods can be safely retried without causing side effects.
🔹 GET, PUT, DELETE, HEAD, OPTIONS → Idempotent
🔹 POST → NOT idempotent
🧠 Why?
Using the correct method:
▪️ Makes APIs predictable
▪️ Enables retries in network failures
▪️ Helps with caching, monitoring, and debugging
SQL Tip – Avoid Scalar Functions in SELECT for Performance
🚫 Bad (Scalar function kills performance on large data)
✅ Good (Inline logic or apply in WHERE/CTE for better performance)
Example:
🚫 Bad (Scalar function kills performance on large data)
✅ Good (Inline logic or apply in WHERE/CTE for better performance)
Example:
April 8, 2025 at 1:05 PM
SQL Tip – Avoid Scalar Functions in SELECT for Performance
🚫 Bad (Scalar function kills performance on large data)
✅ Good (Inline logic or apply in WHERE/CTE for better performance)
Example:
🚫 Bad (Scalar function kills performance on large data)
✅ Good (Inline logic or apply in WHERE/CTE for better performance)
Example:
.NET DI Lifetime Tips:
🔹 Singleton - one of instance for entire app
🔹 Scoped - one instance per request
🔹 Transient - new instance every time
🚨 Be careful:
- Dont inject Scoped/Transient into Singleton (causes bugs/memory leaks)
- Use Singleton only for stateless or thread-safe services.
🔹 Singleton - one of instance for entire app
🔹 Scoped - one instance per request
🔹 Transient - new instance every time
🚨 Be careful:
- Dont inject Scoped/Transient into Singleton (causes bugs/memory leaks)
- Use Singleton only for stateless or thread-safe services.
April 8, 2025 at 12:13 PM
.NET DI Lifetime Tips:
🔹 Singleton - one of instance for entire app
🔹 Scoped - one instance per request
🔹 Transient - new instance every time
🚨 Be careful:
- Dont inject Scoped/Transient into Singleton (causes bugs/memory leaks)
- Use Singleton only for stateless or thread-safe services.
🔹 Singleton - one of instance for entire app
🔹 Scoped - one instance per request
🔹 Transient - new instance every time
🚨 Be careful:
- Dont inject Scoped/Transient into Singleton (causes bugs/memory leaks)
- Use Singleton only for stateless or thread-safe services.
LINQ Tip:
Use ToList() after filtering, not before
Why?
🔹 First version loads everything into memory before filtering
🔹 Second version filters at source, better for DB or large collections
🔹 Especially important when using EF Core or APIs with IQueryable
Use ToList() after filtering, not before
Why?
🔹 First version loads everything into memory before filtering
🔹 Second version filters at source, better for DB or large collections
🔹 Especially important when using EF Core or APIs with IQueryable
April 8, 2025 at 10:03 AM
LINQ Tip:
Use ToList() after filtering, not before
Why?
🔹 First version loads everything into memory before filtering
🔹 Second version filters at source, better for DB or large collections
🔹 Especially important when using EF Core or APIs with IQueryable
Use ToList() after filtering, not before
Why?
🔹 First version loads everything into memory before filtering
🔹 Second version filters at source, better for DB or large collections
🔹 Especially important when using EF Core or APIs with IQueryable
Efficient Async Data Streaming with IAsyncEnumerable<T>
Scenario:
You need to process a large dataset (e.g., database records, file lines, etc.), but you don’t want to load everything into memory at once. Using IAsyncEnumerable<T> lets you stream data asynchronously with minimal memory usage.
Scenario:
You need to process a large dataset (e.g., database records, file lines, etc.), but you don’t want to load everything into memory at once. Using IAsyncEnumerable<T> lets you stream data asynchronously with minimal memory usage.
April 8, 2025 at 9:26 AM
Efficient Async Data Streaming with IAsyncEnumerable<T>
Scenario:
You need to process a large dataset (e.g., database records, file lines, etc.), but you don’t want to load everything into memory at once. Using IAsyncEnumerable<T> lets you stream data asynchronously with minimal memory usage.
Scenario:
You need to process a large dataset (e.g., database records, file lines, etc.), but you don’t want to load everything into memory at once. Using IAsyncEnumerable<T> lets you stream data asynchronously with minimal memory usage.
🔹 What is Queue<T>?
Queue<T> is a First-In-First-Out (FIFO) collection in C#.
It means the first item you add is the first one to be removed.
When to use?
- Task scheduling
- Print jobs
- Message handling
- Breadth-first search (BFS) in graphs
Example:
Queue<T> is a First-In-First-Out (FIFO) collection in C#.
It means the first item you add is the first one to be removed.
When to use?
- Task scheduling
- Print jobs
- Message handling
- Breadth-first search (BFS) in graphs
Example:
April 7, 2025 at 7:51 PM
🔹 What is Queue<T>?
Queue<T> is a First-In-First-Out (FIFO) collection in C#.
It means the first item you add is the first one to be removed.
When to use?
- Task scheduling
- Print jobs
- Message handling
- Breadth-first search (BFS) in graphs
Example:
Queue<T> is a First-In-First-Out (FIFO) collection in C#.
It means the first item you add is the first one to be removed.
When to use?
- Task scheduling
- Print jobs
- Message handling
- Breadth-first search (BFS) in graphs
Example:
SQL Tip:
Always monitor and maintain your indexes.
Unused or duplicate indexes = slower writes and wasted space.
Why?
- Clean indexes = faster inserts/updates
- Less I/O, better performance
🔍 Use this to find unused indexes in SQL Server
Always monitor and maintain your indexes.
Unused or duplicate indexes = slower writes and wasted space.
Why?
- Clean indexes = faster inserts/updates
- Less I/O, better performance
🔍 Use this to find unused indexes in SQL Server
April 7, 2025 at 7:16 PM
SQL Tip:
Always monitor and maintain your indexes.
Unused or duplicate indexes = slower writes and wasted space.
Why?
- Clean indexes = faster inserts/updates
- Less I/O, better performance
🔍 Use this to find unused indexes in SQL Server
Always monitor and maintain your indexes.
Unused or duplicate indexes = slower writes and wasted space.
Why?
- Clean indexes = faster inserts/updates
- Less I/O, better performance
🔍 Use this to find unused indexes in SQL Server
LINQ Trip:
Use GroupJoin for efficient one-to-many relationships instead of nested loops.
Why?
🔹 Cleaner than SelectMany + Where
🔹 Ideal for creating master-detail structures in memory
Use GroupJoin for efficient one-to-many relationships instead of nested loops.
Why?
🔹 Cleaner than SelectMany + Where
🔹 Ideal for creating master-detail structures in memory
April 7, 2025 at 11:41 AM
LINQ Trip:
Use GroupJoin for efficient one-to-many relationships instead of nested loops.
Why?
🔹 Cleaner than SelectMany + Where
🔹 Ideal for creating master-detail structures in memory
Use GroupJoin for efficient one-to-many relationships instead of nested loops.
Why?
🔹 Cleaner than SelectMany + Where
🔹 Ideal for creating master-detail structures in memory
SQL Tip:
Use CROSS APPLY for row-wise calculations or to invoke table-valued functions per row.
Why?
🔹Powerful for row-by-row subqueries
🔹Cleaner & faster than correlated subqueries in many cases
Use CROSS APPLY for row-wise calculations or to invoke table-valued functions per row.
Why?
🔹Powerful for row-by-row subqueries
🔹Cleaner & faster than correlated subqueries in many cases
April 7, 2025 at 8:18 AM
SQL Tip:
Use CROSS APPLY for row-wise calculations or to invoke table-valued functions per row.
Why?
🔹Powerful for row-by-row subqueries
🔹Cleaner & faster than correlated subqueries in many cases
Use CROSS APPLY for row-wise calculations or to invoke table-valued functions per row.
Why?
🔹Powerful for row-by-row subqueries
🔹Cleaner & faster than correlated subqueries in many cases
Csharp Tip:
Use async Task for methods so exceptions can be awaited and handled properly.
Pro tip: Use async void only for UI event handlers.
Use async Task for methods so exceptions can be awaited and handled properly.
Pro tip: Use async void only for UI event handlers.
April 6, 2025 at 10:34 PM
Csharp Tip:
Use async Task for methods so exceptions can be awaited and handled properly.
Pro tip: Use async void only for UI event handlers.
Use async Task for methods so exceptions can be awaited and handled properly.
Pro tip: Use async void only for UI event handlers.
Pass by Value vs Pass by Reference
🔹 Pass by Value: A copy of the value is passed to the function. Changes inside the function don’t affect the original variable.
🔹 Pass by Reference: The memory address (reference) is passed. Changes inside the function do affect the original variable.
🔹 Pass by Value: A copy of the value is passed to the function. Changes inside the function don’t affect the original variable.
🔹 Pass by Reference: The memory address (reference) is passed. Changes inside the function do affect the original variable.
April 6, 2025 at 8:23 PM
Pass by Value vs Pass by Reference
🔹 Pass by Value: A copy of the value is passed to the function. Changes inside the function don’t affect the original variable.
🔹 Pass by Reference: The memory address (reference) is passed. Changes inside the function do affect the original variable.
🔹 Pass by Value: A copy of the value is passed to the function. Changes inside the function don’t affect the original variable.
🔹 Pass by Reference: The memory address (reference) is passed. Changes inside the function do affect the original variable.
SQL Tip:
Use EXISTS instead of COUNT(*) > 0 for better performance when checking if rows exist.
✅ EXISTS stops at the first match.
❌ COUNT(*) scans the whole table.
Faster checks = faster queries ⚡
Use EXISTS instead of COUNT(*) > 0 for better performance when checking if rows exist.
✅ EXISTS stops at the first match.
❌ COUNT(*) scans the whole table.
Faster checks = faster queries ⚡
April 6, 2025 at 12:48 PM
SQL Tip:
Use EXISTS instead of COUNT(*) > 0 for better performance when checking if rows exist.
✅ EXISTS stops at the first match.
❌ COUNT(*) scans the whole table.
Faster checks = faster queries ⚡
Use EXISTS instead of COUNT(*) > 0 for better performance when checking if rows exist.
✅ EXISTS stops at the first match.
❌ COUNT(*) scans the whole table.
Faster checks = faster queries ⚡
EF Core Tip – Bulk Update:
Need to update thousands of rows? Avoid looping with .SaveChanges() in EF Core — it's slow.
Use a bulk update library like EFCore.BulkExtensions for massive performance gains.
Bonus: Works for Insert, Delete, Merge too.
Need to update thousands of rows? Avoid looping with .SaveChanges() in EF Core — it's slow.
Use a bulk update library like EFCore.BulkExtensions for massive performance gains.
Bonus: Works for Insert, Delete, Merge too.
April 6, 2025 at 12:33 PM
EF Core Tip – Bulk Update:
Need to update thousands of rows? Avoid looping with .SaveChanges() in EF Core — it's slow.
Use a bulk update library like EFCore.BulkExtensions for massive performance gains.
Bonus: Works for Insert, Delete, Merge too.
Need to update thousands of rows? Avoid looping with .SaveChanges() in EF Core — it's slow.
Use a bulk update library like EFCore.BulkExtensions for massive performance gains.
Bonus: Works for Insert, Delete, Merge too.
Csharp Tip:
Extract magic values into constants to improve readability and maintainability.
Cleaner code = easier maintenance!
Extract magic values into constants to improve readability and maintainability.
Cleaner code = easier maintenance!
April 6, 2025 at 10:04 AM
Csharp Tip:
Extract magic values into constants to improve readability and maintainability.
Cleaner code = easier maintenance!
Extract magic values into constants to improve readability and maintainability.
Cleaner code = easier maintenance!
C# Trick:
Use Dictionary for fast lookups instead of looping!
Instead of searching a list repeatedly, store key-value pairs in a dictionary for O(1) access.
Use Dictionary for fast lookups instead of looping!
Instead of searching a list repeatedly, store key-value pairs in a dictionary for O(1) access.
April 5, 2025 at 10:44 PM
C# Trick:
Use Dictionary for fast lookups instead of looping!
Instead of searching a list repeatedly, store key-value pairs in a dictionary for O(1) access.
Use Dictionary for fast lookups instead of looping!
Instead of searching a list repeatedly, store key-value pairs in a dictionary for O(1) access.
SQL Trick:
Use COALESCE() to return the first non-null value from a list of columns or expressions.
Why it’s awesome:
• Handles null values seamlessly
• You can chain multiple options: COALESCE(col1, col2, 'default')
Cleaner queries, fewer CASE statements!
Use COALESCE() to return the first non-null value from a list of columns or expressions.
Why it’s awesome:
• Handles null values seamlessly
• You can chain multiple options: COALESCE(col1, col2, 'default')
Cleaner queries, fewer CASE statements!
April 5, 2025 at 7:04 PM
SQL Trick:
Use COALESCE() to return the first non-null value from a list of columns or expressions.
Why it’s awesome:
• Handles null values seamlessly
• You can chain multiple options: COALESCE(col1, col2, 'default')
Cleaner queries, fewer CASE statements!
Use COALESCE() to return the first non-null value from a list of columns or expressions.
Why it’s awesome:
• Handles null values seamlessly
• You can chain multiple options: COALESCE(col1, col2, 'default')
Cleaner queries, fewer CASE statements!
Csharp Trick:
Use null-coalescing assignment ??= to simplify default value logic in C# 8.0+.
What it does:
If myList is null, assign it a new list.
Shorter, smarter and safer code!
Use null-coalescing assignment ??= to simplify default value logic in C# 8.0+.
What it does:
If myList is null, assign it a new list.
Shorter, smarter and safer code!
April 5, 2025 at 3:56 PM
Csharp Trick:
Use null-coalescing assignment ??= to simplify default value logic in C# 8.0+.
What it does:
If myList is null, assign it a new list.
Shorter, smarter and safer code!
Use null-coalescing assignment ??= to simplify default value logic in C# 8.0+.
What it does:
If myList is null, assign it a new list.
Shorter, smarter and safer code!