Unexpected char in header

[Drazail]

Environment

library version: 0.11.2
react: 16.13.0
react-native: 0.61.5
OS: Android

Description

there is this strange problem we are facing while trying to make a post request on android:

the header key we pass to the JS API is:

'X-MOBILE-APP-VERSION'

however on the native side RNFetchBlob tries to set the header as:

x-mobıle-app-versıonnull

this issue happens only when device's language is set to Turkish and the header is in caps. ( presumably ,depending on the header, other non ASCII languages should face the same problem)

Speculation

seems to be originating from .toLowerCase() in RNFetchBlobReq.java

StackTrace:

Error RNFetchBlob request error: Unexpected char 0x131 at 5 in header name: x-mobıle-app-versıonnull node_modules/rn-fetch-blob/index.js:307:25 node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:483:12 value node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:135:28 node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:384:8 value node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:134:17 value [native code] value

CodeSample

          const response = await RNFetchBlob
            .config({ timeout: 4000 })
            .fetch('POST', `${URL}`, {
              'Content-Type': 'application/json',
              Accept: 'application/json',
              'X-MOBILE-APP-VERSION': Config.APP_VERSION,
              'X-MOBILE-APP-MARKET': Config.APP_MARKET,
              'User-Agent': await userAgent,
              Authorization: getToken(),
            }, [
              {
                name: 'id', data: id,
              },
            ]);

the following lines seems to be the problem:

 'X-MOBILE-APP-VERSION': Config.APP_VERSION,
 'X-MOBILE-APP-MARKET': Config.APP_MARKET,

[ObidosDev]

Same problem. Good explanation. My user has TR locale and got exact the same error

[ulrellik]

Same here, the 'i' causes problems with another header, but the problem is the same:
RNFetchBlob request error: Unexpected char 0x131 at 0 in header name: ıf-modified-sincenull
The guy has Android Galaxy A71 with Turkish locale and the app sets the header like this: 'If-Modified-Since' so the capital first 'I' has issues.

[eczmustafa]

same problem with Joplin app.

[eczmustafa]

this project seems to be unmaintained but i made a pull request anyway: #762