Add Predis support (#59)

* wip

* Add Predis support

* Enable phpredis extension only for some builds

* Add note about phpredis

* Fix if command

* Revert travis changes & add a version check to predis tests

src/Exceptions/PhpRedisNotInstalledException.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace Stancl\Tenancy\Exceptions;
+
+class PhpRedisNotInstalledException extends \Exception
+{
+    protected $message = 'PhpRedis is not installed. PhpRedis is required for Redis multi-tenancy because Predis does not support prefixes.';
+}

src/StorageDrivers/RedisStorageDriver.php

@@ -71,16 +71,21 @@ class RedisStorageDriver implements StorageDriver
             return "tenants:{$hash}";
         }, $uuids);
 
-        // Apparently, the PREFIX is applied to all functions except scan()
-        $redis_prefix = $this->redis->getOption($this->redis->client()::OPT_PREFIX);
-        $hashes = $hashes ?: $this->redis->scan(null, $redis_prefix.'tenants:*');
-        
-        return array_map(function ($tenant) use ($redis_prefix) {
-            // Left strip $redis_prefix from $tenant
-            if (substr($tenant, 0, strlen($redis_prefix)) == $redis_prefix) {
-                $tenant = substr($tenant, strlen($redis_prefix));
+        if (! $hashes) {
+            // Apparently, the PREFIX is applied to all functions except scan().
+            // Therefore, if the `tenancy` Redis connection has a prefix set
+            // (and PhpRedis is used), prepend the prefix to the search.
+            $redis_prefix = '';
+            if (config('database.redis.client') === 'phpredis') {
+                $redis_prefix = $this->redis->getOption($this->redis->client()::OPT_PREFIX);
             }
-
+            $hashes = array_map(function ($hash) use ($redis_prefix) {
+                // Left strip $redis_prefix from $hash
+                return substr($hash, strlen($redis_prefix));
+            }, $this->redis->scan(null, $redis_prefix.'tenants:*'));
+        }
+        
+        return array_map(function ($tenant) {
             return $this->redis->hgetall($tenant);
         }, $hashes);
     }

src/Traits/BootstrapsTenancy.php

@@ -5,6 +5,8 @@ namespace Stancl\Tenancy\Traits;
 use Stancl\Tenancy\CacheManager;
 use Illuminate\Support\Facades\Redis;
 use Illuminate\Support\Facades\Storage;
+use Symfony\Component\Debug\Exception\FatalThrowableError;
+use Stancl\Tenancy\Exceptions\PhpRedisNotInstalledException;
 
 trait BootstrapsTenancy
 {
@@ -13,7 +15,9 @@ trait BootstrapsTenancy
     public function bootstrap()
     {
         $this->switchDatabaseConnection();
-        $this->setPhpRedisPrefix($this->app['config']['tenancy.redis.prefixed_connections']);
+        if ($this->app['config']['tenancy.redis.tenancy']) {
+            $this->setPhpRedisPrefix($this->app['config']['tenancy.redis.prefixed_connections']);
+        }
         $this->tagCache();
         $this->suffixFilesystemRootPaths();
     }
@@ -28,7 +32,11 @@ trait BootstrapsTenancy
         foreach ($connections as $connection) {
             $prefix = $this->app['config']['tenancy.redis.prefix_base'] . $this->tenant['uuid'];
             $client = Redis::connection($connection)->client();
-            $client->setOption($client::OPT_PREFIX, $prefix);
+            try {
+                $client->setOption($client::OPT_PREFIX, $prefix);
+            } catch (\Throwable $t) {
+                throw new PhpRedisNotInstalledException();
+            }
         }
     }
 

src/config/tenancy.php

@@ -12,6 +12,7 @@ return [
         'suffix' => '',
     ],
     'redis' => [
+        'tenancy' => false,
         'prefix_base' => 'tenant',
         'prefixed_connections' => [
             'default',