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<div><span></span>hi Guillaume，</div>
<div><br>
</div>
<div>Thanks for your reply.</div>
<div><br>
</div>
<div>I think there should be ambiguity description about my question in my first mail. </div>
<div>Actually what I want is to use varnish as a cache service *without backend servers*, clients can push/pull the resource to/from varnish cache storage using specific http method, such as POST/GET. </div>
<div>For example, one client can send " POST /string1 "abcd" " to make a string-"abcd" cached into varnish, other clients could then use "GET /string1" request to get this string. If Get request miss the cache, a 404 error could be sent (through synth command
in vcl_miss<span style="font-size: 10.5pt; line-height: 1.5; background-color: transparent;">). </span></div>
<div><span style="font-size: 10.5pt; line-height: 1.5; background-color: transparent;"><br>
</span></div>
<div>I am not sure whether it's feasible to make the string<span style="font-size: 10.5pt; line-height: 1.5; background-color: transparent;">-"abcd" cached into varnish. Do you have any </span><span style="color: rgb(36, 39, 41); font-family: Arial, 'Helvetica Neue', Helvetica, sans-serif; font-size: 15px; line-height: 22.5px; background-color: transparent;">recommendation</span><span style="color: rgb(36, 39, 41); font-family: Arial, 'Helvetica Neue', Helvetica, sans-serif; font-size: 15px; line-height: 22.5px; background-color: transparent;"> for
this requrement? </span></div>
<div><span style="color: rgb(36, 39, 41); font-family: Arial, 'Helvetica Neue', Helvetica, sans-serif; font-size: 15px; line-height: 22.5px; background-color: transparent;">Thanks again for your attention!</span></div>
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<div><font color="#242729" face="Arial, Helvetica Neue, Helvetica, sans-serif"><span style="font-size: 15px; line-height: 22.5px;"><br>
</span></font></div>
<div><font color="#242729" face="Arial, Helvetica Neue, Helvetica, sans-serif"><span style="font-size: 15px; line-height: 22.5px;">Zafir Yuan</span></font></div>
<div><font color="#242729" face="Arial, Helvetica Neue, Helvetica, sans-serif"><span style="font-size: 15px; line-height: 22.5px;"><br>
</span></font></div>
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<div>eyz12315@live.cn</div>
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<div><b>From:</b> <a href="mailto:guillaume@varnish-software.com">Guillaume Quintard</a></div>
<div><b>Date:</b> 2019-08-12 14:03</div>
<div><b>To:</b> <a href="mailto:eyz12315@live.cn">Yuan Zafir</a></div>
<div><b>CC:</b> <a href="mailto:varnish-misc@varnish-cache.org">varnish-misc</a></div>
<div><b>Subject:</b> Re: How to cache req.body and then use it in response for coming requests in varnish</div>
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<div dir="ltr">Hi,
<div><br>
</div>
<div>There are a few things to do here:</div>
<div>- make sure that if req.method == "POST", you return(hash) from vcl_recv (otherwise, the builtin.vcl (<a href="https://github.com/varnish/Varnish-Cache/blob/4.1/bin/varnishd/builtin.vcl#L63">https://github.com/varnish/Varnish-Cache/blob/4.1/bin/varnishd/builtin.vcl#L63</a>)
will pass)</div>
<div>- but before that, add 'set req.http.x-method = req.method' at the top of vcl_recv, and 'if (bereq.http.x-method == "POST") {set bereq.method = "POST"; }' at the top of vcl_backend_fetch, because for cacheable request, varnish will want to set the method
to "GET", so we need to reset it back</div>
<div><br>
</div>
<div>On top of that:</div>
<div>- you can use req.hash_always_miss (man vcl) to push new content (and avoid just getting the cached response)</div>
<div>- make sure you only cache when the response is OK, otherwise a wrong POST request will mask the previous valid ones</div>
<div>- if you are acting upon the URL of the resource itself, I'd say it should be a PUT/PATCH, rather than a POST, but that's just pedantry at this point</div>
<div>- realize that the content cached is the response returned by the backend, not the body of the request itself. They may be the same, but maybe not (there are ways to do it though)</div>
<div><br>
</div>
<div>Hope that helps</div>
<div>-- </div>
<div>
<div>
<div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature">
<div dir="ltr">Guillaume Quintard<br>
</div>
</div>
</div>
<br>
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<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Sun, Aug 11, 2019 at 10:42 PM Yuan Zafir <<a href="mailto:eyz12315@live.cn">eyz12315@live.cn</a>> wrote:<br>
</div>
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<div><span></span>Hi，<span style="color:rgb(36,39,41);font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;font-size:15px;line-height:inherit;background-color:transparent">I am trying to configure varnish as a simple cache service, which means the content
posted by clients could be cached as an object. The content chould be returned in responses for the coming GET requests(with same url...). I am not sure wether this can be realized by VCL configuration.</span></div>
<p style="margin:0px 0px 1em;padding:0px;border:0px;font-variant-ligatures:normal;font-stretch:inherit;line-height:inherit;font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;font-size:15px;vertical-align:baseline;box-sizing:inherit;clear:both;color:rgb(36,39,41)">
Any recommendation for this situation? Thanks for any help!</p>
<p style="margin:0px 0px 1em;padding:0px;border:0px;font-variant-ligatures:normal;font-stretch:inherit;line-height:inherit;font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;font-size:15px;vertical-align:baseline;box-sizing:inherit;clear:both;color:rgb(36,39,41)">
I was noticed vmod-bodyaccess can cache req.body and then it could be used in bereq(<a href="https://info.varnish-software.com/blog/caching-post-requests-with-varnish" rel="nofollow noreferrer" style="margin:0px;padding:0px;border:0px;font-style:inherit;font-variant:inherit;font-weight:inherit;font-stretch:inherit;line-height:inherit;font-family:inherit;vertical-align:baseline;box-sizing:inherit;color:rgb(0,89,153)" target="_blank">https://info.varnish-software.com/blog/caching-post-requests-with-varnish</a>),
but I do not know how to put it into responses for clients.</p>
<div><br>
</div>
<div>thanks!</div>
<div>Zafir</div>
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<div><a href="mailto:eyz12315@live.cn" target="_blank">eyz12315@live.cn</a></div>
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</span></div>
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