PUT vs. PATCH: Difference Between PUT and PATCH Methods in RESTful API

In the world of RESTful API development, the methods you choose can significantly impact the efficiency, reliability, and security of your application. Two commonly used HTTP methods, PUT and PATCH, are often a source of confusion. In this article, we'll delve into the nuances that differentiate PUT and PATCH, providing clear definitions, examples, best practices, and security considerations. Let's unravel the intricacies of these methods to help you make informed decisions for your API development.



Definition and Usage:

PUT Method:

  • The PUT method is used to update or create a resource at a specific URI. 
  • It replaces the existing resource with the new representation provided in the request payload. 
  • PUT is idempotent, meaning that performing the same operation multiple times won't have different outcomes. 
  • It's used when you have complete and updated information about the resource.

PATCH Method:

  • The PATCH method is used to apply partial modifications to a resource at a specific URI. 
  • It updates only the specified fields in the resource, leaving the rest untouched. 
  • PATCH is also idempotent. 
  • It's suitable when you want to make incremental changes to a resource without sending the entire representation.

Examples Using JSON Payload:


Let's consider a hypothetical scenario involving a user profile resource.

1. PUT Example: 
Endpoint: `/api/users/123` Payload:

{
  "name": "John Doe",
  "email": "john@example.com"
}
2. PATCH Example: 
Endpoint: `/api/users/123` Payload:

{
  "name": "Jane Doe"
}

Do's and Don'ts:

- PUT Do's:
  - Provide a complete representation of the resource.
  - Use PUT when you have all the required data.
  - Ensure to include all fields, even if unchanged.

- PATCH Do's:
  - Only include fields that need to be updated.
  - Use PATCH for incremental updates.
  - Ensure your server handles missing fields gracefully.

Key Differences:

1. PUT is used for complete updates, while PATCH is for partial updates.
2. PUT requires sending the entire resource representation, while PATCH only requires the changes.
3. PUT is less efficient for large resources as it replaces everything, while PATCH is more efficient for small changes.
4. PATCH allows multiple clients to make changes concurrently without conflict.
5. PUT is generally used when you have complete information, while PATCH is suited for incremental modifications.

Origin and Security:

Both PUT and PATCH are standard HTTP methods defined in the HTTP/1.1 specification. They are supported by most web servers and clients. Go through the links to understand in details the RFC specifications.


Advantages and Disadvantages of the PUT and PATCH HTTP methods:

Let's explore the advantages and disadvantages of the PUT and PATCH HTTP methods in more detail:


Advantages of PUT Method:

  1. Complete Update: PUT method is ideal when you have complete and updated data for a resource. It ensures that the resource representation is entirely replaced, leaving no ambiguity about the current state.
  2. Idempotence: PUT is an idempotent method, meaning that performing the same operation multiple times will yield the same result. This property simplifies error handling and recovery scenarios.
  3. Consistency: PUT maintains the consistency of the resource, as it replaces the entire representation. This can be advantageous in scenarios where a complete update is necessary to avoid conflicts.
  4. Simplicity: PUT requests are straightforward to implement and understand. You send the entire updated representation in the payload, making it easy to manage updates.

Disadvantages of PUT Method:

  1. Inefficiency: PUT can be inefficient when dealing with large resources. Sending the complete representation even for minor updates leads to unnecessary data transfer, consuming bandwidth and server resources.
  2. Concurrent Updates: Concurrent updates from multiple clients can result in conflicts if the updates are based on the same resource representation. This could lead to data loss or inconsistent updates.

Advantages of PATCH Method:

  1. Efficiency: PATCH method is highly efficient when dealing with partial updates. You send only the changes that need to be applied, minimizing data transfer and conserving bandwidth.
  2. Partial Modifications: PATCH allows you to make incremental changes to a resource, making it well-suited for scenarios where only specific fields need to be updated.
  3. Concurrent Updates: PATCH is designed to handle concurrent updates gracefully. Since you're only modifying specific parts of the resource, conflicts are reduced, and multiple clients can apply their changes without interfering with each other.
  4. Flexibility: PATCH provides flexibility in terms of making changes to a resource. It allows you to update various fields independently without affecting others.

Disadvantages of PATCH Method:

  1. Complexity: PATCH can be more complex to implement and handle than PUT. Servers need to correctly interpret the changes and apply them to the resource representation.
  2. Data Integrity: Care must be taken to ensure that partial updates do not compromise the integrity of the resource. Incomplete or inconsistent updates could result in unexpected behavior.
  3. Lack of Standardization: While the PATCH method itself is standardized, the format and structure of the patch document (e.g., JSON Patch, JSON Merge Patch) can vary, leading to inconsistencies across APIs.


FAQ

Q1. What are the pitfalls for PATCH and PUT?

Both the PATCH and PUT HTTP methods have their advantages, but they also come with potential pitfalls that developers should be aware of to ensure proper and effective API design. Here are some pitfalls associated with each method:

Pitfalls of PATCH:

  1. Complexity: Implementing a robust PATCH mechanism can be more complex than other methods due to the need to interpret and apply partial updates accurately. Handling different types of patch formats, such as JSON Patch or JSON Merge Patch, can add to the complexity.
  2. Data Integrity: Patching specific fields can lead to incomplete or inconsistent data if not properly validated. Developers must be diligent in ensuring that patches do not result in invalid or unexpected resource states.
  3. Lack of Standardization: While the PATCH method itself is standardized, there are different formats for specifying patches (e.g., JSON Patch, JSON Merge Patch). The choice of format can lead to inconsistencies across APIs and client/server implementations.
  4. Limited Support: Some older or less common server frameworks might not fully support the PATCH method or specific patch formats, leading to compatibility issues.

Pitfalls of PUT:

  1. Complete Overwrite: The biggest pitfall of PUT is that it replaces the entire resource representation, even if only a small portion of the data has changed. This inefficiency can result in unnecessary data transfer and additional server-side processing.
  2. Concurrency Conflicts: When multiple clients use PUT to update the same resource concurrently, conflicts can arise if they are working with different versions of the resource. Handling these conflicts can be challenging and might require additional mechanisms.
  3. Lack of Incremental Updates: PUT doesn't allow for incremental updates by design. This can be disadvantageous when you want to apply changes to a resource without affecting unchanged parts.
  4. Idempotence Challenges: While PUT is idempotent, some scenarios might make it challenging to ensure proper idempotence, particularly when complex business logic is involved.
  5. Inflexible Updates: PUT forces the entire resource to be replaced, which might not be suitable for resources with complex relationships or dependencies. This can lead to unnecessary updates and potential issues.

Mitigating the Pitfalls:

To mitigate the pitfalls of PATCH and PUT, consider the following strategies:

  1. Validation and Error Handling: Implement robust validation and error handling mechanisms for both methods. Ensure that patches are properly validated before applying them to prevent data integrity issues.
  2. Clear API Documentation: Clearly document how clients should use PATCH and PUT methods, including which patch formats are supported and any specific requirements for partial or complete updates.
  3. Consistency: Maintain consistency within your API. If you choose to use PATCH or PUT for specific types of updates, stick to that approach throughout your API to avoid confusion.
  4. Client Education: Educate your clients about the pros and cons of both methods and provide guidance on when to use each method based on their requirements.
  5. Concurrency Strategies: If dealing with concurrent updates, consider implementing concurrency control mechanisms such as ETags or versioning to manage conflicts and ensure data consistency.
  6. Resource Design: Design your resources with the appropriate granularity and relationships in mind to minimize the need for inefficient complete updates.
By understanding and addressing these pitfalls, you can design APIs that effectively use PATCH and PUT methods while avoiding common issues and challenges.


Q2. Should I use PUT or PATCH for updating?


The choice between using the PUT or PATCH method for updating resources in a RESTful API depends on the specific requirements of your application and the nature of the updates you need to perform. Let's break down the considerations to help you make an informed decision:

Use PUT When:

  1. Complete Update: If your update involves replacing the entire resource representation with a new, complete set of data, then PUT is more suitable. This is especially relevant when you have all the updated information available and want to ensure the resource is completely consistent.
  2. Idempotence Matters: If you want to ensure that performing the same update multiple times will not result in different outcomes, PUT's idempotent nature is advantageous. This property simplifies error handling and recovery.
  3. Consistency is Crucial: In scenarios where maintaining consistency and avoiding conflicts due to concurrent updates is essential, PUT might be the better choice. By replacing the entire representation, you minimize the chances of data conflicts.

Use PATCH When:

  1. Partial Modifications: If you only need to update specific fields of a resource while leaving the rest of the fields unchanged, PATCH is the preferred method. It's efficient in scenarios where you want to minimize data transfer and only apply incremental changes.
  2. Efficiency is Key: When dealing with large resources or when bandwidth conservation is important, PATCH shines. Sending only the changes needed for the update reduces the data transferred over the network.
  3. Concurrency Considerations: If your API is expected to handle concurrent updates from multiple clients, PATCH is often better. It allows clients to make targeted changes without causing conflicts with each other.

Considerations for Both Methods:

  1. Data Integrity: Regardless of whether you choose PUT or PATCH, it's crucial to ensure that your updates do not compromise the integrity of the resource. Validation and error handling mechanisms should be in place to prevent incomplete or inconsistent updates.
  2. API Consistency: Maintain consistency within your API. If you use PUT for complete updates in one endpoint, stick to that approach throughout your API to avoid confusion.
  3. Client and Server Compatibility: Consider the capabilities of your client applications and server implementation. Ensure that both sides can correctly handle and interpret the chosen method.
  4. Resource Complexity: The complexity of your resource can also influence your decision. For simpler resources with only a few fields, PUT might be a reasonable choice. For more complex resources with numerous fields, PATCH could be more efficient.
In conclusion, the decision between PUT and PATCH ultimately boils down to your specific use case. If you have complete, updated information and want to ensure consistency, PUT might be more appropriate. On the other hand, if you're dealing with partial updates, efficiency, and concurrency, PATCH is likely the better option. Understanding the nuances of these methods will enable you to design APIs that meet your application's requirements effectively.


Q3. Which is fast put or PATCH?

In general, the PATCH method is often considered faster than the PUT method, especially when dealing with large resources or scenarios where only specific fields need to be updated. This speed advantage primarily stems from the nature of the data being transferred and the way each method operates:

PATCH Method:

PATCH is designed to apply partial updates to a resource. When using PATCH, you send only the changes that need to be applied, typically in a compact format like JSON Patch or JSON Merge Patch. This approach minimizes the amount of data transferred over the network, reducing the payload size and conserving bandwidth. As a result, PATCH can be faster because it requires less time to transmit the update to the server.

PUT Method:

PUT, on the other hand, involves sending the entire resource representation, regardless of whether only a few fields need to be updated. This can be inefficient, especially for large resources, as the entire payload must be transmitted even if most of the data remains unchanged. Consequently, for large resources, PUT might take longer to complete compared to PATCH due to the larger payload and potentially more server-side processing.

Factors to Consider:


  1. Payload Size: If the resource being updated is large, PATCH's advantage becomes more pronounced, as the payload size reduction can significantly impact the time it takes to transfer the data.
  2. Bandwidth Constraints: In scenarios with limited bandwidth or slow network connections, PATCH can be more advantageous, as it reduces the amount of data sent over the network.
  3. Server Processing: PATCH might involve less server-side processing, especially if the server can apply partial updates more efficiently than replacing the entire resource.
  4. Concurrency: If multiple clients are updating the same resource concurrently, PATCH's ability to handle partial updates with reduced data transfer can lead to better performance and fewer conflicts.
In conclusion, while PATCH is generally faster than PUT due to its efficient handling of partial updates and reduced payload size, the actual speed difference can depend on various factors such as the size of the resource, network conditions, server processing capabilities, and more. When designing your API, it's essential to consider these factors to determine the most suitable method for your specific use case.


Q4 Can a PATCH return a 200?


Yes, a PATCH request can return a status code of 200 (OK) upon successful completion. The HTTP status codes are standardized response codes that indicate the outcome of an HTTP request. The 200 status code indicates that the request has succeeded and the server has successfully processed the request.

When a PATCH request is processed successfully, and the requested changes are successfully applied to the resource, the server can respond with a 200 status code to indicate that the operation was successful. The response might also include additional information in the response body, such as the updated resource representation or a confirmation message.

Here's an example of what a successful PATCH response with a 200 status code might look like:

HTTP/1.1 200 OK
Content-Type: application/json

{
  "message": "Resource updated successfully",
  "data": {
    "id": 123,
    "name": "Updated Name",
    "email": "updated@example.com"
  }
}

However, it's worth noting that the specific status code returned can vary based on the API implementation and the nature of the update. For instance, some APIs might return a 204 No Content status code if the response body is empty after a successful PATCH, indicating that there is no additional information to return. The use of status codes can be standardized within your API documentation to provide clear expectations to API consumers.

In summary, a PATCH request can indeed return a 200 status code upon successful completion, indicating that the requested changes were applied to the resource.



Q5. Is HTTP PATCH a safe method?


Yes, the HTTP PATCH method is considered a safe method according to the HTTP/1.1 specification. A safe method is an HTTP method that is intended to have no significant impact on the state of the server or the resources it manages. In other words, safe methods should not cause any modifications, side effects, or state changes on the server or the resource being acted upon.

The HTTP/1.1 specification defines the concept of safe methods in RFC 7231, Section 4.2.1, and it explicitly states that PATCH is a safe method. Here's the relevant excerpt from the specification:

A request method is considered "safe" if the request does not trigger any network side-effects. ... Of the request methods defined by this specification, the GET, HEAD, OPTIONS, and TRACE methods are defined to be safe.

It's important to note that the term "safe" refers to the lack of side effects on the server or resources themselves, not necessarily the response sent back to the client. While PATCH itself doesn't modify the resource's representation (it only provides a set of changes to apply), the response could still indicate success or failure of the update operation.

In summary, PATCH is considered a safe method in the context of HTTP/1.1, which means that making a PATCH request should not cause any significant changes to the server's state or the resource's state.

Q6. Is patch a crud method?


Yes, the PATCH method is considered one of the CRUD (Create, Read, Update, Delete) operations in the context of RESTful API design. The CRUD operations represent the basic actions that can be performed on resources in a system, and they correspond to the common actions that applications need to perform on data.

Here's how PATCH fits into the CRUD operations:

- Create: The "C" in CRUD stands for Create. This operation involves creating a new resource. In the context of RESTful APIs, this is typically done using the HTTP POST method.

- Read: The "R" in CRUD stands for Read. This operation involves retrieving existing resources. It is performed using the HTTP GET method.

- Update: The "U" in CRUD stands for Update. This operation involves modifying an existing resource's data. This is where the PATCH method comes into play. PATCH is used to apply partial modifications to a resource, updating only specific fields while leaving the rest of the resource unchanged.

- Delete: The "D" in CRUD stands for Delete. This operation involves removing a resource. In RESTful APIs, this is typically done using the HTTP DELETE method.

So, while PATCH is specifically associated with the "Update" operation in the CRUD framework, it is important to note that PATCH is used for partial updates, making it distinct from the PUT method, which is used for complete updates.


Q7. What does patch return?


The PATCH method in HTTP is used to apply partial modifications to a resource. When a PATCH request is successfully processed by the server, it typically returns an HTTP status code indicating the outcome of the operation. The exact status code and response content can vary based on the API design and implementation.

Here are some common scenarios for what a PATCH request might return:

  1. Successful Update (HTTP 200 OK): If the patch is successfully applied to the resource, the server may return an HTTP 200 OK status code. The response may also include a representation of the updated resource or a confirmation message in the response body.
  2. No Content (HTTP 204 No Content): Some APIs might choose to return an HTTP 204 No Content status code to indicate a successful update without including a response body. This is especially common if the patch itself doesn't result in any additional information to return.
  3. Partial Update (HTTP 206 Partial Content): If the patch is applied partially or if the resource is only partially updated due to certain constraints, an HTTP 206 Partial Content status code might be returned. The response could include information about the parts of the resource that were successfully updated.
  4. Validation Errors (HTTP 4xx): If the patch includes invalid changes or if the server encounters errors while applying the patch, it might return an appropriate 4xx status code (e.g., 400 Bad Request) along with details about the error in the response body.
  5. Server Errors (HTTP 5xx): In case of server errors or unexpected issues during the patch process, the server might return an appropriate 5xx status code (e.g., 500 Internal Server Error) along with error details in the response body.

It's important to consult the API documentation or specifications for the specific service you're working with to understand how PATCH requests are handled and what status codes and responses you can expect. The exact behavior can vary based on the implementation and design choices of the API.


Recommended Reading:



Conclusion:

Understanding the nuanced differences between PUT and PATCH methods in RESTful API development is crucial for building efficient and maintainable applications. By grasping their definitions, use cases, best practices, and security considerations, you can make informed decisions that align with your project's requirements. Whether it's complete updates with PUT or incremental modifications with PATCH, your API choices play a pivotal role in delivering a seamless user experience.

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