Possible to overide a foreach variable parameter within itself? - php

Question

I have made a small script which uses the Twitch API. The API only allows a maximum of 100 results per query. I would like to have this query carry on until there are no more results.
My theory behind this, is to run a foreach or while loop and increment the offset by 1 each time.
My problem however, is that I cannot change the foreach parameters within itself.
Is there anyway of executing this efficiently without causing an infinite loop?
Here is my current code:
<?php
$newcurrentFollower = 0;
$offset=0;
$i = 100;
$json = json_decode(file_get_contents("https://api.twitch.tv/kraken/channels/greatbritishbg/follows?limit=25&offset=".$offset));
foreach ($json->follows as $follow)
{
echo $follow->user->name . ' (' . $newcurrentFollower . ')' . "<br>";
$newcurrentFollower++;
$offset++;
$json = json_decode(file_get_contents("https://api.twitch.tv/kraken/channels/greatbritishbg/follows?limit=25&offset=".$offset));
}
?>
Using a While loop:
while($i < $total)
{
$json = json_decode(file_get_contents("https://api.twitch.tv/kraken/channels/greatbritishbg/follows?limit=25&offset=".$offset));
echo $json->follows->user->name . ' (' . $newcurrentFollower . ')' . "<br>";
$newcurrentFollower++;
$offset++;
$i++;
}
Ends up echoing this (No names are successfully being grabbed):
Here is the API part for $json->follows:
https://github.com/justintv/Twitch-API/blob/master/v2_resources/channels.md#get-channelschannelfollows

Answer 1

You can use this:
$offset = 0;
$count = 1;
do {
$response = json_decode(file_get_contents(
'https://api.twitch.tv/kraken/channels/greatbritishbg/follows?limit=100&offset=' . $offset
));
foreach($response->follows as $follow) {
echo $follow->user->name . ' (' . ($count++) . ')' . "</br>";
}
$offset+=25;
} while (!empty($response->follows));

Answer 2

You want to use a while loop here, not just a foreach. Basically:
while (the HTTP request returns results)
{
foreach ($json->follows as $follow)
{
do stuff
}
increment offset so the next request returns the next one not already processed
}
The trickiest part is going to be getting the while condition right so that it returns false when the request gets no more results, and will depend on what the API actually returns if there are no more results.
Also important, the cleanest way would be to have the HTTP request occur as part of the while condition, but if you need to do some complicated computation of the JSON return to check the condition, you can put an initial HTTP request before the loop, and then do another request at the end of each while loop iteration.

Answer 3

The problem is you're only capturing the key not the value. Place it into a datastructure to access the information.
Honestly I find a recursive function much more effective than a iterative/loop approach then just update a datatable or list before the next call. It's simple, uses cursors, lightweight and does the job. Reusable if you use generics on it too.
This code will be in c#, however I know with minor changes you'll be able to get it working in php with ease.
query = //follower object get request//
private void doProcessFollowers(string query)
{
HTTPParse followerData = new HTTPParse(); //custom json wrapper. using the basic is fine. Careful with your cons though
var newRoot = followerData.createFollowersRoot(query); // generates a class populated by json
if (newRoot[0]._cursor != null)
{
populateUserDataTable(newRoot); //update dataset
doProcessFollowers(newRoot[0]._links.next); //recurse
}
}
Anyway - This just allows you to roll through the cursors without needing to worry about indexes - unless you specifically want them for whatever reason. If you're working with generics you can just reuse this code without issue. Find a generic example below. All you need to do to make it reuseable is pass the correct class within the <> of the method call. Can work for any custom class that you use to parse json data with. Which is basically what the 'createfollowerroot()' is in the above code, except that's hard typed.
Also I know it's in c# and the topic is php, with a few minor changes to syntax you'll get it working easily.
Anyway Hope this helped somebody
Generic example:
public static List<T> rootSerialize<T>(JsonTextReader reader)
{
List<T> outputData = new List<T>();
while (reader.Read())
{
JsonSerializer serializer = new JsonSerializer();
var tempData = serializer.Deserialize<T>(reader);
outputData.Add(tempData);
}
return outputData;
}