React Native Apollo Client无法获取完整数据问题求助

Let's break down the most likely reasons why your query works smoothly in GraphiQL but returns null for the level2 field in React Native's Apollo Client, along with actionable checks to resolve this:

• Cache Normalization Conflicts
  Apollo Client automatically normalizes data in its cache using unique identifiers (by default, id or _id). If the level2 object from your server lacks a valid unique ID, or if the ID format (e.g., string vs. numeric) doesn't match what's already stored in the cache, Apollo might fail to resolve the field and return null.

  • Verify if your server's level2 response includes a unique identifier field. If not, define a custom dataIdFromObject function in your Apollo Client config to tell Apollo how to uniquely identify level2 objects.
  • You can temporarily disable cache normalization (not recommended for long-term use) by passing addTypename: false to InMemoryCache to test if this is the root cause.

• Mismatched Variables or Request Context
  Even if your query string looks identical, double-check that the variables you're passing in React Native (abc: 1) are exactly the same as what you used in GraphiQL. It's easy to accidentally pass a mismatched value (like a string "1" instead of the number 1) without noticing.

  • Also confirm that your Apollo Client request includes the same headers (such as auth tokens) as your GraphiQL request. Missing or invalid authentication could cause the server to return partial data, with level2 set to null.
  • Add logging to your Apollo Client link to inspect the exact query, variables, and headers being sent:

    import { ApolloLink } from '@apollo/client';
    
    const loggingLink = new ApolloLink((operation, forward) => {
      console.log('Query being sent:', operation.query.loc.source.body);
      console.log('Variables:', operation.variables);
      console.log('Request headers:', operation.getContext().headers);
      return forward(operation);
    });
    

• Stale Cache Interference
  Apollo might be returning stale cached data where level2 was null from a previous request. Test this by forcing the query to skip the cache and fetch directly from the server:

  client.query({
    query: myQuery,
    variables: { abc: 1 },
    fetchPolicy: 'network-only'
  }).then((resp) => {
    console.log('Raw server response:', resp.data);
  });
  

If level2 is now populated correctly, you'll need to fix how your cache is being updated—for example, using refetchQueries after mutations or ensuring cache IDs are consistent across requests.

• Field or Type Definition Mismatches
  Double-check that your client-side query's field selection for level2 matches exactly what the server returns. For instance, if the server returns level3A (PascalCase) but your query asks for level3a (camelCase), Apollo might silently drop the field and resolve level2 as null.

  • Also ensure your client's GraphQL type definitions (if using code generation) are in sync with the server's schema. Outdated types can cause unexpected cache resolution issues.

• React Native Network Edge Cases
  While less likely, React Native's network stack can behave differently from browsers. Check your server logs to confirm that the request from Apollo Client is actually receiving the full response (including valid level2 data). If the server returns the correct data but Apollo isn't parsing it, you might need to troubleshoot JSON parsing or link configuration issues.

内容的提问来源于stack exchange，提问作者leofontes