Google Global Address List for Domain limited to 250 results [rehash] - google-api

Question

Reposting due to lack of answers
I'm trying to query Google Global Address List for a specific domain, being led by this answer here (Specifically the answer by Jay Lee).
It's all well and good and works perfectly in Google's OAuth Playground, however it seems to be limited to 250 users. Given that this feature seems completely undocumented, and that I can't tell by looking at their github repo (specifically this file), does anyone know how to query for the next 250 users or how to set the number of results?
Thank you!

Answer 1

My last answer was converted into a comment, but I now have a complete answer to this question.
EDIT: I repeatedly mention JSON but you don't need to parse this in JSON to get the syncToken. Google will provide you the syncToken regardless.
The Google GAL API seems to operate in a similar manner to the Google Calendar or YouTube API's "nextPageToken" parameter, which allows you to query the next page of results as long as you have a token.
The Google GAL uses the "syncToken" parameter as a replacement. Much like the other Google API's, if you append this syncToken to the end of your URL, you will get the next page of results. Note that I was unable to get the startIndex parameter to work (which allows you to begin at a specific item in the JSON), so if you are trying to get a specific result through the query you will most likely have to parse the entire JSON file. Inside the parsed JSON, there should be a key called "gal$syncToken." You can find it in the json right before the "entry" key/array which is where all of the global domain contacts are listed.
Here is an example of what it would look like:
"gal$syncToken": {
"$t": "0_1001_17011_AAN3FFNH2AEJ3SFBKZDRS36AHRXHND47YACXLGFJF5QBXCSQLUK57EX3LC765CU5IWG6ZXWHPS5WKHSDFJ26LRI5FRIVIQ3Z532PWKG3ZG45JW3RVCDZMWK5LLLHZSCBTJH5U6Q4LZRG4PKWQE42AOIPC4VJCZQIP5MBJHNUBZZJNLKISKETTQ6DNTRAPTI"
},
Your syncToken will look different. To get the next page of results, Google actually provides a link that already has the syncToken pre-appended:
{
"rel": "next",
"type": "application/atom+xml",
"href": "https://www.google.com/m8/feeds/gal/example.com/full?sync-token=0_1001_17011_AAN3FFNH2AEJ3SFBKZDRS36AYRXHND47YACXLGFJF5QBXCSQLUK57EX3LC765CU5IWG6ZXWHPS5WKHSDFJ26LRI5FRIVIQ3Z562PWKG3ZG45JW3RVCDZMWK5LLLH6SCBTJH5U6Q4LZRG4PKWQE42AOIPC4VJCZQIP5MBJHNUBZZJNLKBSKETTQ6DNTRAPTI"
},
However, this will only give you the next 250 results. If you want more on each page, you can append the max-results parameter to this and have Google spit it back out in JSON format.
https://www.google.com/m8/feeds/gal/example.com/full?sync-token=INSERT_SYNCTOKEN_HERE&alt=json&max-results=10000
Hope this helped anyone seeing this. The Google GAL seems to be largely undocumented for the most part and I was unable to find an answer to this question anywhere else on the internet. If anyone from Google can confirm that this is the best method for accomplishing this that would be great!