caching - Varnish: purge cache every time user hits "like" button -

-

i need implement like/dislike functionality (for anonymous users there no need sign up). problem content served varnish , need display actual number of likes.

i'm wondering how it's done on website stackoverflow. assuming pages cached in varnish (for anonymous users only), every time user votes on answer/question, page needs purged cache. right? current number of votes needs visible other users.

what approach in situation? should send purge varnish every time user hits "like" button?

a common way of implementing button , display client side in javascript instead. avoids issue slightly.

assuming pressing leads post request hitting single varnish server, can make object invalidated/replaced in different ways. using purge , vcl restart better way this.

of course there slight race here, other clients served old page while ongoing.


Comments

Post a Comment

Popular posts from this blog

How to check data type in C++? -

-
i'm new c++, i've been using python. i'm trying check type of variable of value stored in objects i'm working on. remember in python there comand isinstance use condition run commands, if next value string, a, , if it's int b. is there way check what's data type on variable in c++? example: in python had array math operation, each character in field [3,"+",2] as read array separate ints strings isinstance command if isinstance(list[0],int): aux1.append(list[0]) list=list[1:] else: if isinstance(lista[0],str): aux2.append(list[0 list=list[1:] now in c++ need similar, time each character in node linked list , again, need separate them, ints in linked list, , strings in linked list what seem struggling c++ statically , (relatively) typed language. discussion each of these terms mean refer this other question , it's explained there better could. first of should sure need...
Read more

javascript - Is getTimezoneOffset() stable during daylight saving transition? -

-
i have date time below conversion logic in javascript converting utc time passed timezone's local time. wondering logic work fine during daylight transition? if not remedy that? can't use third party library. have use pure javascript or angular js. function mytime() { var d1= document.getelementbyid("txtdate").value; var zoffset = document.getelementbyid("txtoffset").value; console.log("date1",d1); var d2 = new date(d1.replace(/ /g,'t')); var d3= d2.gettime()+(d2.gettimezoneoffset()*60000); console.log("date2",d2); console.log("date3",d3); var d4 = new date(d3 + (3600000 * zoffset)); console.log("date3",d3); console.log("date 4",d4); var d5 = d4.tolocaletimestring(); console.log("date 5",d5); ...
Read more

sql server - SQL Query returns one result, does not return 0 or NULL result -

-
i trying query list advisers , provide count of active students each. can list advisers have 1 student, exclude more 1, can not return advisers 0 or null count. select advisors.advisorid, advisors.firstname, advisors.lastname, count(case students.isactive when '1' 1 else null end) "number of students" advisors, students advisors.advisorid=students.advisorid group advisors.advisorid, advisors.firstname, advisors.lastname having count(case students.isactive when '1' 1 else null end)='1' counts active studnets, , returns advisor list advisor 1 student, advisers 0 students come blank. missing? select advisors.advisorid, advisors.firstname, advisors.lastname, count(case students.isactive when '1' 1 else null end) "number of students" advisors, students advisors.advisorid=students.advisorid group advisors.advisorid, advisors.firstname, advisors.lastname having count(case students.isactive when '1' 1 else null end) null ...
Read more