new feature: Add docs about conditional write for s3

[wcy-fdu]

Feature Description

Recently s3 introduce conditional write, which can check if an object exists before creating it. This feature can help user more easily prevent the application from overwriting any existing objects when uploading data.
refer to https://aws.amazon.com/about-aws/whats-new/2024/08/amazon-s3-conditional-writes/?nc1=h_ls

Problem and Solution

Additional Context

No response

Are you willing to contribute to the development of this feature?

• Yes, I am willing to contribute to the development of this feature.

[Xuanwo]

Already supported by write_with(path).if_none_match("*"). We can improvide our documantation and tests to make it clear.

For example, we can add a test that writes with if_none_match("*") to a path where a file exists; we should have a condition not matched error.

[wcy-fdu]

Already supported by write_with(path).if_none_match("*"). We can improvide our documantation and tests to make it clear.

So fast, this feature is only available on August 20th.

[Xuanwo]

So fast, this feature is only available on August 20th.

Luckily, AWS S3 implemented this feature in the same way OpenDAL designed its API...

[ForestLH]

I am new to opendal, can i try this? Thanks.

[Xuanwo]

I am new to opendal, can i try this? Thanks.

Sure! We can add if_none_match for s3 write first, for example:

opendal/core/src/services/s3/core.rs

Lines 398 to 399 in dd02e29

	if let Some(if_none_match) = args.if_none_match() {
	req = req.header(IF_NONE_MATCH, if_none_match);

[ForestLH]

I am new to opendal, can i try this? Thanks.

Sure! We can add if_none_match for s3 write first, for example:

opendal/core/src/services/s3/core.rs

Lines 398 to 399 in dd02e29

	if let Some(if_none_match) = args.if_none_match() {
	req = req.header(IF_NONE_MATCH, if_none_match);

Thanks! That's very helpful to me.