Curl cached response. org and enter the URL to run the test.

Curl cached response. Without the session token it will just ignore the request for subsequent pages. If it doesn't work, you can do it the old-fashioned way, by adding a unique querystring parameter. From the Everything curl book, reusing curl connections by combining command lines can provide a performance increase, but the connection cache and other caches are cleared each time an individual Response headers in HTTP communications contain key metadata about the server’s response, including status codes, content types, caching policies, and cookies. I was wondering if it was possible to have the fetched information cached on my server? For example, when a curl displays this data to the terminal by default, so if you invoke curl to do an operation and it is about to write data to the terminal, it disables the progress meter as otherwise it would mess up the output mixing progress meter and response data. Nov 23, 2017 · A 301 Moved Permanently is an HTTP response status code indicating that the requested resource has been permanently moved to a new URL provided by the Location response header. Client URL Library 6. It informs the browser that requested content has not changed between the last visit, and so the browser can serve it from its cache instead of downloading the resource again. Responses Every HTTP request includes an HTTP response. a response body), it should be ignored by clients. Virtually all libcurl-using applications need Mar 10, 2015 · 0 I would like to cache curl responses, and I found out a couple of ways to do that, but all of them include saving a response to the file, and than retrieving it. I'm not sure how much gets cached by curl, but I have ran into several cases where I am looking for new content and I want to ensure the content is new and no chance of being cached. g. It is If-Modified-Since or If-Unmodified-Since. When talking HTTPS, this sends SNI for the name in the URL and curl verifies the server's response to make sure it serves for the name in the URL. How can I do that? The HTTP 304 Not Modified status code is found among the HTTP response status codes. It confirms that the resource cached by the client is still valid and that curl --retry 5 --retry-connrefused https://example. Mar 12, 2024 · Accept: Communicates the media types that the client is willing to receive from the server. The 3xx category of response codes are used to indicate redirection messages to the client, such that the client will become aware that a redirection to a different resource or URL should take place. With a free account they may not cache something until many requests for that resource start coming in. I'm using PHP cURL to fetch information from another website and insert it into my page. You have already added cache-control headers in your amplify. There is no build-in way to do this, but we can still cut out the headers from the response message, if CURLOPT_HEADER is true. If you are unable to see Pragma headers after attempting to enable them using above curl command, we recommend Based on the information available, it appears that the caching of API responses is a feature of Amplitude's system. How can I do that? The book: Everything curl This is a detailed and totally free book, available online (and as a PDF as a link from there) that explains everything there is to know about curl, libcurl and the associated project. Name resolves will be kept in memory and used for this number of seconds. To retrieve the application’s caches, make a GET request to /actuator/caches, as shown in the following curl-based example: Bypass Fastly cache to check Adobe Commerce sites If the Fastly service returns incorrect headers, you can create a VCL snippet that allows you to submit requests that bypass the Fastly cache. Objectives This tutorial will explain the basics of the cURL command and how to use it to transfer data to or from a server, along with some of its most frequently used options. On cache hits, “Cache Hit Time” indicates the time spent looking up the response, and “Compute Input Time” / “Compute Time” / “Compute Output Time” are not recorded. Mar 18, 2024 · A quick and practical guide to displaying request headers using curl. HSTS cache The HSTS status for a certain server name is set in a response header and has an expire time. Short options Command line options pass on information to curl about how you want it to behave. curl displays this data to the terminal by default, so if you invoke curl to do an operation and it is about to write data to the terminal, it disables the progress meter as otherwise it would mess up the output mixing progress meter and response data. To make it NAME top curl - transfer a URL SYNOPSIS top curl [options / URLs] DESCRIPTION top curl is a tool for transferring data from or to a server using URLs. To make it print a hexdump of everything, use the --trace argument. There is no explicit way to flush the dns cache other than closing the handle or possibly Jun 12, 2013 · From my understanding, after making the first request with curl, i need to save the returned etag for later use, so that on all subsequent requests (till the etag invalidates on server) i use the cached version because the server will return a 304 header and an empty response. 2 Will curl be I am attempting to use curl's --resolve option to connect to the specified IP address when performing the HTTP request, but curl keeps reverting back to the IP address as retrieved by my local DNS cache/resolver. com Retry on any and all errors The most aggressive form of retry is for the cases where you know that the URL is supposed to work and you do not tolerate any failures. An HTTP response however always has response headers. Oct 7, 2022 · The command specifies wait=200 but curl returns in ~60 seconds. I am able to access internet from a browser. For instance: Checking the cache status of an object on your website can help when troubleshooting problems. See Bypass Fastly cache. Such header is send by the browser for cached resources, but curl does not send it drnextgis commented Mar 24, 2021 I think health check response should never be cached: Dec 11, 2012 · HTTP protocol allows a client to specify a time condition for the document it requests. By leveraging advanced decision-making mechanisms, we maintain an extensive amount of cached data, that is ready to be served if called upon. " in the code? The code I'm using is from Jeff's post he Apr 12, 2021 · Getting the HTTP response headers with cURL in PHP is not straight forward. Oct 15, 2022 · It is worth noting that the cache response you get for the homepage is not necessarily the same response you’ll get for other pages and assets on the site, but the presence of the header is a dead giveaway. Is this correct? Response headers in HTTP communications contain key metadata about the server’s response, including status codes, content types, caching policies, and cookies. org, or a visual tool like Cloudflare Optics plugin. You are expected to get top performance already without doing anything extra in particular. 4 Does PHP/CURL have dependencies? Development 8. When you request a page with a cached response available, you'll receive the cached data, ensuring much faster access to the information you need with a 100% success rate. Invoke curl and tell it which file to use as a hsts cache: Learn how to use cURL for HTTP/HTTPS requests, SSL diagnostics, and performance optimization. Try adding an arbitrary query string variable to the URL to see if you can reproduce it. 6 Can you please change the curl/libcurl license to XXXX? 6. For example, let's see what curl might Nov 21, 2022 · When using the cURL command, remember that it is only an HTTP client and does not cache any requests on the client side. Once the test is done, go to Details page and click on the resource that you want to check if it’s served from CloudFlare CDN. The status for every HSTS hostname needs to be saved in a file for curl to pick it up and to update the status and expire time. I will then give examples on how to manage output cache keys within an ASP. The API Management service has a set of endpoints, the majority of which are set to cache-control: no-cache… May 16, 2023 · Hi, I have configured a Squid proxy with ntlm authentication (Ubuntu, with Samba Active Directory Domain Controller). We measure the time taken to calculate the factorial using time. 7 What are my obligations when using libcurl in my commercial apps? PHP/CURL Issues 7. They help clarify how data is delivered and can indicate where to troubleshoot if issues arise. How do I use curl Unix/Linux command line option to test a server with If-Modified-Since condition and validate Last-Modified settings? Jul 4, 2025 · The HTTP Cache-Control header holds directives (instructions) in both requests and responses that control caching in browsers and shared caches (e. Jun 30, 2020 · The short answer is no. 3 Can I perform multiple requests using the same handle? 7. It adds informational tests and prefix them with '*'. TCP\_MEM\_HIT : Object was on disk and in the memory cache. Below, you find a list of return codes as of the time of this writing If the response cache is enabled for a given model (see Response Cache docs for more info), total inference times may be affected by response cache lookup times. If you are using Acquia Edge Akamai, Acquia typically keeps these headers off, and it’s a best practice to keep them off for the Akamai production network. Let’s dive into the methods provided by the BasicCurl class and Dec 27, 2016 · The curl application sets the variables curl_response_data and curl_response_code. Feb 21, 2023 · Curl does not cache any requests on the client side; therefore, any caching when using Curl occurs on the server side. --resolve inserts the address into curl's DNS cache, so it effectively makes curl believe that is the address it got when it resolved the name. Is this correct? Learn how to use ScraperAPI’s caching feature in cURL to boost speed, success rate, and efficiency. 2 Who wrote PHP/CURL? 7. I can see the… Jul 23, 2025 · The Requests library is the go-to tool for making HTTP requests in Python. In a previous post I showed how we can use in-memory caching to improve performance within a . The below steps will give an option to use curl to achieve the requirement. Dec 23, 2022 · Preventing Caching with HTTP Headers [Curl/Bash Code] To prevent caching, the client must send the correct minimum set of three HTTP headers that work on all servers and proxies (Cache-Control, Pragma, and Expires). For example: retry up to 12 times for all errors: You can use cURL to fetch the HTTP headers of a file on a CDN, and check the x-cache header to see if a file is HIT (served from cache), MISS (not served from cache), or BYPASS (not checked against cache). cacheable response) and that cached response was a hit for this new request. Exit code A lot of effort has gone into the project to make curl return a usable exit code when something goes wrong and it always returns 0 (zero) when the operation went as planned. Tell curl to follow redirects In curl's tradition of only doing the basics unless you tell it differently, it does not follow HTTP redirects by default. time() and log it using Flask's built-in logger. This lets transfers skip unnecessary loading and parsing time that comes from loading and handling the sometimes rather big CA cert bundles. If you write a shell script or batch file that invokes curl, you can always check the return code to detect problems in the invoked command. curl_response_data can also be headers/body or json if requested. In this guide, we’ll focus on making GET requests using cURL and use the Free Photos API as an example. Like you can ask curl to switch on verbose mode with the -v Mar 12, 2025 · Want to test your web server and see if static files are properly cached? Curl can help and with some scripting even automate the task for you. This response reduces download times and server load. The cf-cache-status is shown under Response Headers. To bypass the server-side cache, you can use the Cache-Control HTTP header to control the caching behavior. This is done to ensure efficient processing of requests, especially those that may have a longer duration. Reusing a connection instead of creating a new one offers significant Response caching is a technique for reducing server load by caching GraphQL query operation results. These curl recipes show you how to debug curl requests to see what it's sending and receiving. In a previous post I explained what output caching is, compared it to response caching, and showed how Dec 3, 2022 · Welcome to today’s post. How to use libcurl. If the response cache is enabled for a given model (see Response Cache docs for more info), total inference times may be affected by response cache lookup times. To make it print the full communication, including the request headers, SSL certificate information, response headers, and response body, use the -v command line argument. TCP\_COOKIE\_DENY : Denied access on cookie authentication (if centralized or Sep 18, 2023 · It encapsulates common cURL operations into reusable methods, making it easier to interact with external APIs and web services. And since the service takes ~80 seconds to respond, I get no response (but I do get a response if I use wait=1000). Mar 18, 2024 · When we use the cURL command, we must note that cURL is only an HTTP client, and it doesn’t cache any request on the client-side. In today’s post I will be explaining how to manage output response cache keys within a web application, and how they result in the application performance. All options This is a table of available options for curl_easy_setopt(). 304 Not Modified The HTTP 304 Not Modified redirection response status code indicates that there is no need to retransmit the requested resources. We‘ll cover: What […] Verbose If your curl command does not execute or return what you expected it to, your first gut reaction should always be to run the command with the -v / --verbose option to get more information. Sep 25, 2024 · Your server is sending cache-control: max-age=86000 - effectively saying to Cloudflare "hey, this response should be cached for 86000 seconds". Learn how to use its intuitive API to send requests and interact with the web. In today’s post I will discuss how we can use response caching in a web server to limit the number of requests that are made from a client, and to reduce the workload of the server in response generation. The Art Of Scripting HTTP Requests Using curl Background This document assumes that you are familiar with HTML and general networking. Feb 7, 2025 · One of the most versatile and powerful tools for this purpose is cURL. Problem is that, for same URL, I always get a MISS CA cert cache With some of the TLS backends curl supports, it builds a CA cert store cache in memory and keeps it there for subsequent transfers to use. When one transfer has completed it keeps N connections alive in a connection pool (sometimes also called connection cache) so that a subsequent transfer that happens to be able to reuse one of the existing connections can use it instead of creating a new one. Therefore, any caching while using this command happens on the server-side. The increasing amount of applications moving to the web has made "HTTP Scripting" more frequently requested and wanted. To bypass the server-side cache, we can try some tweaks on the HTTP request we’re sending. Covering a wide range of curl options, tricks, and tips. Remember, the API itself is provided solely for demonstration purposes—the main focus here is on mastering GET requests with cURL. Use the -L, --location option to tell it to do that. Curl certainly doesn't retain anything between executions unless configured to do so (e. Such header is send by the browser for cached resources, but curl does not send it Jul 4, 2025 · The HTTP Cache-Control header holds directives (instructions) in both requests and responses that control caching in browsers and shared caches (e. Apr 8, 2011 · I found sometimes browser can't get cookies from my website, so I use curl to check the headers, and the information is: C:\Documents and Settings\jack>curl http://localhost -I Nov 14, 2024 · Welcome to today’s post. To investigate cache responses returned by this header, use services like Redbot, webpagetest. Server served it without hitting the disk. Jun 11, 2015 · The curl client isn't caching files, but the remote server network might well be. We’ll also explain the basics of HTTP requests and how to perform them with the cURL command, along with some useful things you can do. txt); do content="$(curl Mar 16, 2025 · curl displays this data to the terminal by default, so if you invoke curl to do an operation and it is about to write data to the terminal, it disables the progress meter as otherwise it would mess up the output mixing progress meter and response data. : setting a cookie file). Jul 15, 2010 · Command line curl can display response header by using -D option, but I want to see what request header it is sending. Using --retry-all-errors makes curl treat all transfers failures as reason for retry. js files, but you can verify if these headers are being set correctly by inspecting the response headers of a request to your server. If you support a lot of sites like we do at work, you can script it with bash and get a neat list of which ones use Cloudflare cache: for url in $(head -n800 urls. After you add the VCL snippet, use cURL commands to submit requests to the origin server from the specified IP address. cached decorator caches the result for 10 minutes (timeout=600). libcurl is designed and intended to run as fast as possible by default. 0 web API application. If content is still returned (Aka. In today’s post we will be using Jun 13, 2017 · Method 3: Check Response Header with WebPageTest Visit webpagetest. TCP\_DENIED : Denied access to the client for whatever reason. Aug 26, 2019 · Check Cloudflare cache status On Linux, UNIX or macOS it's very easy to check the cache status with the cURL or wget command. The ubiquitous cURL utility makes it easy to craft customized HTTP requests and inspect headers. 1 Why does curl use C89? 8. Cache-Control: Directs how caching of the response should be handled, specifying directives like max-age and no-cache. curl is powered by libcurl for all Learn how to handle and fix request timeout issues in cURL commands. This response code is sent when the request is a conditional GET or HEAD request with an If-None-Match or an If-Modified-Since header and the condition evaluates to 'false'. NET Core 7. The "no-cache" request directive indicates that a cache MUST NOT use a stored response to satisfy the request without successful validation on the origin server. It seems http-cache not working for php curl or i do wrong to create function curl to work using http cache. Method 4: Check Response Header with curl curl is a tool to transfer data from or to a server, using one of curl however, does not remember or cache any redirects at all so to it, there is really no difference between permanent and temporary redirects. config. The cached results are typically refreshed after a certain period, which can sometimes lead to the same results being returned for multiple queries within that period. reuse handles Servebolt HTML Cache After enabling Static Files + Full-Page Cache in the Admin Panel of your site and enabling the HTML cache in our Servebolt Optimizer, we can use the cache headers to verify whether the HTML cache is working or not. Using options like --include or --head reveals these headers, allowing Jun 14, 2022 · This guide outlines the most popular curl examples, along with a description of what each command does. Practical solutions for common timeout problems in API requests and web scraping. Headers enable passing additional context, authentication, caching instructions, cookies and more. To be able to automatically extract information from the web, to fake users, to post or upload data to web servers are all important tasks Sep 5, 2014 · See CURLOPT_DNS_CACHE_TIMEOUT: Pass a long, this sets the timeout in seconds. An example below using this very site, as it relies on Cloudflare heavily. The idea is to fetch the web page with any of these commands, retrieve the response header, then filter out the header with grep command. Response body The response body is passed to the write callback and the response headers to the header callback. yml and next. When verbose mode is enabled, curl gets more talkative and explains and shows a lot more of its doings. If the cached copy is outdated, it will typically be Oct 30, 2023 · HTTP headers allow clients and servers to send metadata during requests and responses. (CDN servers require making a GET request to initiate caching) For example:. Also, by default your Cloudflare account will have a different cache on each Cloudflare edge location, which means if requests end up routed to different edge locations the cache will be In UNIX based systems you can use "curl -I -X GET [url]" to check your file headers. Sep 26, 2025 · The CF-Cache-Status header output indicates whether a resource is cached or not. curl supports over two hundred different options. I suspect the server is expecting a session token of some sort (cookie or other HTTP header are my guess). Using cURL to send HTTP headers cURL provides the -H (shortcut for --header) option to include customer headers in HTTP requests. Learn how to use curl. , Proxies, CDNs). By default, libcurl caches this info for 60 seconds. May 17, 2021 · in your command line and see all of the options it offers. Are you sure Cloudflare actually supports Cache-Control from the client (which can vary depending on your plan as well)? As far as I know they generally don't let the clients control the cache behavior, but only the server. Apr 12, 2021 · When a server receives a HEAD request, it should only return the response headers of the given resource. Command line options When telling curl to do something, you invoke curl with zero, one or several command-line options to accompany the URL or set of URLs you want the transfer to be about. The problem here is that my code needs to work with curl_getinfo() object, which is available only after the curl_exec call is finished. output header is response 304 means it load from cache. In the highlighted area of cache headers, we can see the following response headers: x-frontend-cache: HIT. The -H 'Cache-Control: no-cache' argument is not guaranteed to work because the remote server or any proxy layers in between can ignore it. Any ideas why on some links that I try to access using HttpWebRequest I am getting "The remote server returned an error: (304) Not Modified. Aug 10, 2023 · Cloudflare doesn't guarantee every server response will always be cached, especially for a free account. Explore step-by-step commands, tips for debugging, and use cases. Set to zero to completely disable caching, or set to -1 to make the cached entries remain forever. By default, cURL displays only the response body and omits headers. The HTTP 304 Not Modified status code is found among the HTTP response status codes. Feb 13, 2018 · I’ve been using Http-Cache following slim documentation… It works very well in browser and ajax. If the CDN is geographically distributed, the headers may also show which server the response originated from. In this comprehensive guide, you‘ll learn all about working with headers using cURL. I make requests from curl, wget and Chrome to verify the cache response. An HTTP response is a set of metadata and a response body, where the body can occasionally be zero bytes and thus nonexistent. org and enter the URL to run the test. By default, curl only prints the response body. Connection reuse libcurl keeps a pool of old connections alive. NET Core Web API web service. It can be a ScraperAPI's caching system unlocks a new level of efficiency. I'm not sure how much gets cached by curl, but I have… Feb 5, 2025 · NOTE: Adding " Pragma: akamai-x-cache-on " to your curl command might not be sufficient to enable Pragma headers on Akamai. Mar 12, 2025 · This curl cheat sheet contains commands and examples of common tasks that can be performed with curl. Apr 22, 2012 · 304 means Not Modified and is send in response of requests that contain If-Modified-Since header. Feb 17, 2020 · I have a nginx cache proxy that gets content from an apache origin server. As a result, any caching that occurs while using this command occurs on the server. Cached results update every 10 mins for fresh data. Oct 22, 2023 · The @cache. Busting cache with curl. Clients may send a HTTP HEAD request to check if a resource has been updated by comparing the response headers with a timestamp of a cached copy. How to build them from source or perhaps how the curl project accepts contributions. When libcurl resolves the IP addresses of a hostname it stores the result in its DNS cache (with a default life-time of 60 seconds), so that subsequent lookups can use the cached data immediately instead of doing the (potentially slow) resolve operation again. 1 What is PHP/CURL? 7. But, after I have test using php curl to call my api. You can use the Fastly control panel or the curl command (an open-source command line tool for transferring data with URL syntax from or to a server using one of many supported protocols) to check Fastly's cache nodes for a cached object, and you can use the information provided to examine the object Jun 12, 2013 · From my understanding, after making the first request with curl, i need to save the returned etag for later use, so that on all subsequent requests (till the etag invalidates on server) i use the cached version because the server will return a 304 header and an empty response. It supports these protocols: DICT, FILE, FTP, FTPS, GOPHER, GOPHERS, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, MQTT, POP3, POP3S, RTMP, RTMPS, RTSP, SCP, SFTP, SMB, SMBS, SMTP, SMTPS, TELNET, TFTP, WS and WSS. Performance This section collects general advice on what you can do as an application author to get the maximum performance out of libcurl. Dec 13, 2023 · In some occasions where we are doing performance related analysis, we may need to do a direct call to a particular service and get the time spent between request and response. Here's my thought on 💭 cURL Command Without Using Cache | Baeldung on Linux Busting cache with curl. Using options like --include or --head reveals these headers, allowing curl displays this data to the terminal by default, so if you invoke curl to do an operation and it is about to write data to the terminal, it disables the progress meter as otherwise it would mess up the output mixing progress meter and response data. A Windows host which is a domain member is configured to use that proxy. There are however some common things to look at or perhaps mistakes to avoid. Oct 1, 2023 · I have a Front Door / CDN with caching enabled that uses the response from an API Management service to determine what specific content to cache. For incoming GraphQL Query operations with the same variable values, the same response is returned from a cache instead of executed again. gu5fdfbf 6gg7m qs89jyvah fcwj ifni sph8 aeejw x4fu 4vs7rp vcpp