The query hash that is generated by apollo-android does not match the query hash that is generated by apollo-link-persisted-queries

[tareq-khandaker-ck]

Problem Description

The query hash that is generated by apollo-android does not match the query hash that is generated by apollo-link-persisted-queries.

Investigation

1. I took a query and the query hash generated by apollo-android and found that query hash was different from the query hash that apollo-link-persisted-queries generates for the same query.

2. I wrote a command-line utility that performed the same steps as apollo-link-persisted-queries:

   a. Read a query string.

   b. Perform a graphql parse on the output of a.

   c. Perform a graphql print on the output of b.

   d. Compute the SHA256 hash on the output of c.

3. I found that my hash matched the one that apollo-link-persisted-queries generates.

4. I looked at the code and saw that https://github.com/apollographql/apollo-android/blob/master/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/OperationTypeSpecBuilder.kt#L58 filters out newlines while https://github.com/apollographql/apollo-link-persisted-queries/blob/master/src/index.ts#L28-L31 does not.

5. I added newline stripping to my utility in 2.

6. I found that my hash now matched the one generated by apollo-android.

Proposed Solutions

There are two possible, mutually-exclusive solutions:

Either make the change inside apollo-android

Change https://github.com/apollographql/apollo-android/blob/master/apollo-compiler/src/main/kotlin/com/apollographql/apollo/compiler/OperationTypeSpecBuilder.kt#L58 to be:

        .initializer("\$S", operation.sourceWithFragments?.sha256())

Or make the change inside apollo-link-persisted-queries

Change https://github.com/apollographql/apollo-link-persisted-queries/blob/master/src/index.ts#L30 to be:

    .update(print(query).replace(/\n/g, ''))

Related PR

I raised the same issue in apollo-android here: apollographql/apollo-kotlin#1283 .