i have question regarding working of package. how writes redis db ?
this settings redis -
caches = { 'default': { 'backend': 'redis_cache.rediscache', 'location': '/var/run/redis/redis.sock', 'options': { 'db': 2, }, }, } this views file,
def postview(request): print("working") #post_list = post.objects.all() if cache.get("posts") == none: post_list = post.objects.all() print("going cached") = cache.get("aman") print("aman ", a) cache.set("posts", post_list, timeout=60*100*10) print("cached") else : post_list = cache.get("posts") aman = cache.get("aman") print(aman, " aman's job") print("already present in cache") context = {"post_list" : post_list} print("problem") return render(request, 'post_list.html', context) @cache_page(60*15*10, key_prefix="cache_redis") def testview(request): post_list = cache.get("posts") print("post_list is", post_list) return render(request, 'post_list.html', {"post_list":post_list}) @cache_page(60*25*10, key_prefix="cache_test") def new(request): print("hey") print("cache_page working") return httpresponse("hello, mohammed") this redis -cli ,
luvpreet@dhari-inspiron-3542:~/test_venv_wrapper/test_redis/cache_redis$ redis-cli 127.0.0.1:6379> select 2 ok 127.0.0.1:6379[2]> set "a" "aman" ok 127.0.0.1:6379[2]> set ":1:a" "theman" ok 127.0.0.1:6379[2]> keys * 1) "a" 2)":1:views.decorators.cache.cache_page..get.ad00468064711919773512f81be0dbc4.d41d8cd98f00b204e9800998ecf8427e.en-us.utc" 3) ":1:posts" 4) ":1:a" 5) ":1:aman" 6) ":1:views.decorators.cache.cache_header.cache_test.ad00468064711919773512f81be0dbc4.en-us.utc" 7) ":1:views.decorators.cache.cache_header..ad00468064711919773512f81be0dbc4.en-us.utc" 8) ":1:b" 9)":1:views.decorators.cache.cache_page.cache_test.get.ad00468064711919773512f81be0dbc4.d41d8cd98f00b204e9800998ecf8427e.en-us.utc" 10) "aman" 127.0.0.1:6379[2]> ":1:a" "theman" 127.0.0.1:6379[2]> "a" "aman" this corresponding redis-cli monitor
luvpreet@dhari-inspiron-3542:~/test_venv_wrapper/test_redis/cache_redis$ redis-cli monitor ok 1491412249.001149 [0 unix:/var/run/redis/redis.sock] "info" 1491412249.086196 [0 127.0.0.1:44984] "select" "2" 1491412250.001249 [0 unix:/var/run/redis/redis.sock] "info" 1491412257.001426 [0 unix:/var/run/redis/redis.sock] "info" 1491412257.423536 [2 127.0.0.1:44984] "set" "a" "aman" 1491412258.001311 [0 unix:/var/run/redis/redis.sock] "info" 1491412269.001211 [0 unix:/var/run/redis/redis.sock] "info" 1491412269.820886 [2 127.0.0.1:44984] "set" ":1:a" "theman" 1491412270.000741 [0 unix:/var/run/redis/redis.sock] "info" 1491412272.955386 [2 127.0.0.1:44984] "keys" "*" 1491412273.001121 [0 unix:/var/run/redis/redis.sock] "info" 1491412340.991928 [2 127.0.0.1:44984] "get" ":1:a" 1491412341.002001 [0 unix:/var/run/redis/redis.sock] "info" 1491412344.106985 [2 127.0.0.1:44984] "get" "a" 1491412345.001677 [0 unix:/var/run/redis/redis.sock] "info" this means data manually inserting database 2 available , can fetch through redis-cli.
but when try fetch manually entered data django-app python shell, happens,
>>> django.core.cache import cache >>> cache.get("a") traceback (most recent call last): file "<console>", line 1, in <module> file "/usr/local/lib/python2.7/dist-packages/redis_cache/backends/base.py", line 33, in wrapped return method(self, client, key, *args, **kwargs) file "/usr/local/lib/python2.7/dist-packages/redis_cache/backends/base.py", line 259, in value = self.get_value(value) file "/usr/local/lib/python2.7/dist-packages/redis_cache/backends/base.py", line 210, in get_value value = self.deserialize(value) file "/usr/local/lib/python2.7/dist-packages/redis_cache/backends/base.py", line 197, in deserialize return self.serializer.deserialize(value) file "/usr/local/lib/python2.7/dist-packages/redis_cache/serializers.py", line 42, in deserialize return pickle.loads(force_bytes(value)) unpicklingerror: not find mark here redis-cli monitor corresponding it,
ok 1491413058.004167 [0 unix:/var/run/redis/redis.sock] "info" 1491413059.002746 [0 unix:/var/run/redis/redis.sock] "info" 1491413060.663292 [2 unix:/var/run/redis/redis.sock] "get" ":1:a" 1491413061.001167 [0 unix:/var/run/redis/redis.sock] "info" why cannot access data written manually ? know adds prefix data written through django. prefix ":1:key_name". that's why added 2 keys namely "a" , ":1:a". when try access "a", call ":1:a".
but error comes up. so, might writing data redis other way. please tell me error , tell me way in writes data.
the error gettting not data retreival error, data being retreived, not in correct pickle format.
- when setting data manually, being set in byte format, not pickled format.
when set data through django-redis, data first serialized using cpickle, , stored redis pickled string.
when retreive data stored through django-redis, retreived pickle serialized string, , deserialized corresponding python datatype.
- your manually entered data string type, not in correct pickle format, hence though gets retreived, cannot converted corresponding python type, , pickling error.
- the solution use django-redis in django shell or code store , retreive data, entering data manually breaks serialization contract.
example:
>>> django.core.cache import cache >>> cache.set("the_key","aman") true >>> cache.get("the_key") 'aman' >>> dhruv@dhruvpathak:~$ redis-cli 127.0.0.1:6379> keys * 1) ":1:the_key" 127.0.0.1:6379> ":1:the_key" "\x80\x02u\x04amanq\x01." 127.0.0.1:6379> set "the_manual_key" "aman" ok 127.0.0.1:6379> "the_manual_key" "aman" 
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