Question: m_context.set_sending_requst([&md5_header] what does it do?

[yxiang92128]

Hi,

I see many blob test/examples (tests/cloud_blob_test.cpp) for instance includes the following code snippet and I couldn't figure out what it intend to do. Can somebody please explain?
utility::string_t md5_header;
m_context.set_sending_request([&md5_header] (web::http::http_request& request, azure::storage::operation_context)
{
if (!request.headers().match(web::http::header_names::content_md5, md5_header))
{
md5_header.clear();
}
});

Thanks,

Yang

[katmsft]

This is to extract the md5 header calculated on the run and evaluate it later, somewhere below the code you mentioned there is this line:

CHECK_UTF8_EQUAL(expect_md5_header ? md5 : utility::string_t(), md5_header);

This is checking that the md5_header is correctly calculated.

[yxiang92128]

Thanks for the reply but I have a follow up question concerning the "ms_header_range_get_content_md5" flag in the request header when get_blob is called in
src/blob_request_factory.cpp.

I don't think the conent md5 for the range is returned anywhere in APIs specified in was/blob.h.
How do I check for that Range MD5? Is there a sample code for doing so?

thanks,

Yang

[Jinming-Hu]

The range MD5 is used to validate data integrity internally and isn't exposed to user directly. If you want to check it, you can provide an operation_context parameter and check HTTP response header after the request is finished.

Take a look at
class operation_context
class operation_context::_get_impl()
class _operation_context::request_results()
class request_result::content_md5()

[Jinming-Hu]

We're going to close this issue because of inactivity, feel free to reopen it if you have any further questions.