How to find a Github file 's SHA blob

The docs for updating a file specify that you will need to provide the SHA for the file you will be replacing. The easiest way would be to query github for that, too. For example:

> curl https://api.github.com/repos/testacc01/testrepo01/contents/test.txt{  "name": "test.txt",  "path": "test.txt",  "sha": "4f8a0fd8ab3537b85a64dcffa1487f4196164d78",  "size": 13, …

So, you can see what the SHA is in the "sha" field of the JSON response. Use that when you formulate your request to update the file with a new version. After you have successfully updated the file, the file will have a new SHA that you will need to request before it can be updated again. (Unless, I guess, your next update goes on a different branch.)

If you use GraphQL API v4, you can use the following to find the sha of a specific file :

{  repository(owner: "testacc01", name: "testrepo01") {    object(expression: "master:test.txt") {      ... on Blob {        oid      }    }  }}

Try it in the explorer

If you don't want to hit the api, you could generate the SHA yourself. Git generates the SHA by concatenating a header in the form of blob {content.length} {null byte} and the contents of your file. For example:

content = "what is up, doc?"header = "blob #{content.bytesize}\0"combined = header + content # will be "blob 16\u0000what is up, doc?"sha1 = Digest::SHA1.hexdigest(combined)

Source: https://git-scm.com/book/en/v2/Git-Internals-Git-Objects