Why would a script work for the developer, but not for the client?

[Lynn_10]

I just hired a developer in India to write an API upload script for my cloud server. He just finished it and it works fine for him, but I've tried it in all browsers and it doesn't work at all for me. I'm in the UK. What could cause this?

[rproffitt]

The list of "What could cause this?" can be long. You mention cloud, API upload so my first thoughts which are guesses since I see no code or much details are:

1. The DNS lookup could fail since what they used and what you use can differ.
2. Your ISP could restrict traffic.
3. Your server if this runs on a server could have restrictions.
4. The script has a defect.

Remember these must be guesses given the story so far. Also the code could be flat out broken and really doesn't work.

Did you try a Javascript LINT (code checker)?

[Schol-R-LEA]

One more possibility (of many) that comes to my mind is that the environment of the cloud server differs from that of the development system, and that there is either some subtle dependency which is lacking, or some added feature on the server which is blocking the script from functioning.

Do you know what sort of system the dev host is, and what sort of system the cloud server runs? If they are (for example) different versions of Windows, or different Linux distributions, that may account for the different behavior.

Similarly, assuming this is a RESTful or otherwise web-based application (which it sounds as if it is), are they using different HTTPS servers for the testing and production servers (e.g., Apache vs. Nginx vs. IIS)? Are there any specific server configs required by the script which the developer neglected to mention, or which you (or the cloud server admin, if that's someone else) may have overlooked?

Also, assuming this is querying a database, how does the test database compare to the production database?

How is the script being tested on the dev host? Is the developer certain that it is being run through the HTTPS server, and not as a purely local script somehow?

Is the script primarily client-side or server-side, or are there separate components for each?

[Dani]

Is the developer confused as to why it's working for him but not you?

It could nto be working for you for a whole bunch of reasons, including the developer's code is referencing files on his local file system. Or, as other people have pointed out, the DNS hasn't propagated to you yet, etc.

[Lynn_10]

I really appreciate your comments. He seems to have got it working for me now. My only problem is that the server API doesn't currently support chunked uploads so I can only seem to upload small files. Are there any workarounds for that?