if-modified-since

问题 I am fetching and parsing an RSS feed (https://www.mangaupdates.com/rss.php) with Discord.js/Node.js. I'm currently trying to add a conditional If-Modified-Since header to make a conditional GET request to the RSS feed. Here is my code: fetch(mangaUpdatesRSS, { method: 'GET', headers: {'If-Modified-Since': new Date().toUTCString()} }) .then(res => { console.log(res.status); The response status is always 200 even though it should only be making a request if it's been modified since the time of

问题 In my python application I have to read many web pages to collect data. To decrease the http calls I would like to fetch only changed pages. My problem is that my code always tells me that the pages have been changed (code 200) but in reality it is not. This is my code: from models import mytab import re import urllib2 from wsgiref.handlers import format_date_time from datetime import datetime from time import mktime def url_change(): urls = mytab.objects.all() # this is some urls: # http:/

问题 I want to implement a "get changed values" capability in my API. For example, say I have the following REST API call: GET /ws/school/7/student This gets all the students in school #7. Unfortunately, this may be a lot. So, I want to modify the API to return only the student records that have been modified since a certain time. (The use case is that a nightly process runs from another system to pull all the students from my system to theirs.) I see http://blog.mugunthkumar.com/articles/restful

问题 I am trying to retrieve a page which uses js and database to load. The loading takes about 2 to 3 mins. I am able to get the page where it would show "Please wait 2 to 3 mins for the page to be loaded." But not able to retrieve the page after it is loaded. I have already tried the following: 1.) Using mirror method in the Mechanize. But the response content is not decoded. Hence the file is gibberish. (Also tried to write a similar method as mirror method which would decode the response

问题 I use prototype on the client side. I need to change picture on the page without reloading. So in my .js file I change the src of a picture and it works ok. But I also need that if the same image requested, it would alse request the server to know if this image has changed, and reload if needed. Server sends last-modified header, and if gets if-modified-Since, then checks, and either sends new image or 304 Not Modified response. When the image is requested the first time, server replies with

问题 I use prototype on the client side. I need to change picture on the page without reloading. So in my .js file I change the src of a picture and it works ok. But I also need that if the same image requested, it would alse request the server to know if this image has changed, and reload if needed. Server sends last-modified header, and if gets if-modified-Since, then checks, and either sends new image or 304 Not Modified response. When the image is requested the first time, server replies with

问题 My Browser isn't sending back an If-Modified-Since Header for PHP generated Content on the first request my script sends: (Status-Line) HTTP/1.1 200 OK Date Thu, 21 Jan 2010 08:55:25 GMT Server Apache/2.2.11 (Win32) PHP/5.2.9-1 X-Powered-By PHP/5.2.9-1 Pragma no-cache x-ua-compatible IE=8;FF=3;OtherUA=4 Last-Modfied Sat, 02 Jan 2010 02:02:20 GMT Content-Length 28453 Etag b98e0795b509be20146f58e06fbb624f Keep-Alive timeout=5, max=90 Connection Keep-Alive Content-Type image/png it on the second

问题 I wanted to know how to check the server response of " If-Modified-Since " header sent by my browser. I am not sure how do I achieve it. Any help would be a great deal to me, Thanks. 回答1: Check the HTTP response code (e.g., using curl ). If the resource is not modified you get a 304 response, else, in the non-error case, a 200 . 来源： https://stackoverflow.com/questions/6661924/if-modified-since-header

问题 Expressjs automatically send etags. I would like to know how the etag is generated..is it based on the content that is generated dynamically by the get routine. or is there way I can mainpulate it, by not even going through the process of generating the content(dynamic content - from DB) and pass back etag as same. may be a middleware which start with just checking if it is valid session id and pass back the same etag that the client gives or may be based of the url + session id..that way it

问题 I want browsers to always add (except first time) "If-Modified-Since" request header to avoid unnecessary traffic. Response headers are: Accept-Ranges:bytes Cache-Control:max-age=0, must-revalidate Connection:Keep-Alive Content-Length:2683 Content-Type:text/html; charset=UTF-8 Date:Thu, 05 Apr 2012 13:06:19 GMT Keep-Alive:timeout=15, max=497 Last-Modified:Thu, 05 Apr 2012 13:05:11 GMT Server:Apache/2.2.21 (Red Hat) FF 11 and IE 9 both send "If-Modified-Since" and get 304 in response but