No _links section found

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Nicolas Battaglia

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Mar 9, 2022, 10:10:54 AM3/9/22
to DSpace Technical Support
Dear Tim

Before SSL certificate actualization, we have the next error on browser console:

hal-endpoint.service.ts:42 No _links section found at https://dspaceapi-test.uai.edu.ar/server/api


In my case, all the links works fine for me (response with a json)
image.png




frontend  and backend now were secure in browser


any idea? 

thanks in advanec






Tim Donohue

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Mar 9, 2022, 10:31:16 AM3/9/22
to Nicolas Battaglia, DSpace Technical Support
Hi Nicolas,

This is one of our "Common Installation Issues" documented in the installation guide.  Please see those docs for details on how to fix that problem:


If you hit further issues, let us know on the list.  But, always check those Common Installation Issues first, as we've documented a lot of the fixes right there in the installation guide.

Good luck

Tim

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Sent: Wednesday, March 9, 2022 9:10 AM
To: DSpace Technical Support <dspac...@googlegroups.com>
Subject: [dspace-tech] No _links section found
 
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Nicolas Battaglia

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Mar 9, 2022, 11:11:46 AM3/9/22
to Tim Donohue, DSpace Technical Support
Hi Tim

I've seen that documentation before send my first email, but i can't resolve the issue. Our dspace implementation worked fine  until the certificate expired, then we create a new certificate and replace older, restart all the services but nothing works. We run dspace under windows and we have a pfx certificate. We run a few commands with openssl to extract .key and .crt (same process that we used first time), and we use apache 2.4 as reverse proxy.

Really i not understand the problem

whe have 2 dspace installation, test and production .En both cases we have the same error, but only try to replace certificate in test environment. Production environment gets the error and gets an untrusted site message, because it have and older certificate.

we  did  not make any changes in configuration files, 


Tim Donohue

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Mar 9, 2022, 1:03:15 PM3/9/22
to Nicolas Battaglia, DSpace Technical Support
Hi Nicolas,

In that "common installation issue" I linked to, you'll notice that it says it can be caused by "a possible SSL Certificate issue" where the "REST API's SSL certificate is either untrusted (by the frontend) or expired". 


If all you changed was the certificate, then chances are the new certificate is either not being "seen" by the frontend, or it's not being trusted by the fronted.  This might mean that your Apache settings for the certificate are to blame... or it could be that you are using a Self-signed certificate which the frontend isn't trusting.. see also this other common issue: https://wiki.lyrasis.org/display/DSDOC7x/Installing+DSpace#InstallingDSpace-UsingaSelf-SignedSSLCertificatecausestheFrontendtonotbeabletoaccesstheBackend

Those are my best guesses based on what you've provided.  If you have more questions, let us know on this list.

Tim

From: Nicolas Battaglia <ing.nicola...@gmail.com>
Sent: Wednesday, March 9, 2022 10:11 AM
To: Tim Donohue <tim.d...@lyrasis.org>
Cc: DSpace Technical Support <dspac...@googlegroups.com>
Subject: Re: [dspace-tech] No _links section found
 

Nicolas Battaglia

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Mar 9, 2022, 1:58:15 PM3/9/22
to Tim Donohue, DSpace Technical Support
Thanks Tim

In this case, frontend and backend are running at same server with Apache24 as reverse proxy. Both sites are now secured in browser but frontend still getting same error of links sections

by te way,  the link in the error: hal-endpoint.service.ts:42 No _links section found at https://dspaceapi-test.uai.edu.ar/server/api  works fine, get a json with a _links section full of links and anyone works fine

really, i'm getting crazy

thanks a lot

Mohammad S. AlMutairi

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Mar 9, 2022, 3:22:20 PM3/9/22
to DSpace Technical Support
On Wednesday, March 9, 2022 at 9:58:15 PM UTC+3 ing.nicola...@gmail.com wrote:
really, i'm getting crazy

You shouldn't be. There is always a technical explanation to what you think is weird to happen. I guess it has to do to the way you setup your dspace environment but you haven't provided enough information as ( Number of servers and OS's used, Webservers used on each of the servers you have, How the SSL termination is done? Reverse-Proxy configuration, DSpace backend and Frontend configuration details and so on ... ) for anyone in the list willing to help to be able to help.

Nicolas Battaglia

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Mar 9, 2022, 6:14:06 PM3/9/22
to Mohammad S. AlMutairi, DSpace Technical Support
Thanks Mohammad!

My Dspace was working fine until my ssl certificate is expired. After that, create a new certificate using the same way that i created previous one. Its a PFx certificate, then  i extracted .crt and .key using openssl. I've a apache working as reverse proxy in a same server with both  services: tomcat with backend, nodejs with frontend.

I can use Hal browser without problem, and it is secured by ssl certificate: https://dspaceapi-test.uai.edu.ar/server/#/server/api

I can access frontend using https too, https://repositorio-test.uai.edu.ar/ by still get same error about links sections


image.png

 https://dspaceapi-test.uai.edu.ar/server/api this link get this json, and every link in this document, works fine

image.png




I think is a ssl issue, but i can't resolve it. My certificates are not SelfSigned or let's encrypt style too.  

thanks again

Nicolas





Mohammad S. AlMutairi

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Mar 10, 2022, 7:19:30 AM3/10/22
to DSpace Technical Support
Hello Nicolas,

The certificate is O.K from what I see from here. I still think it has to do on how you configured dspace. Can you post the output of yarn config:check:rest and the apache config file?. Also can you ping the backend from inside the test environment server and match it to the internal IP address and post the IP address you see here. ( If you prefer you can send them in private message ).

Cheers, 

Marwa Saada

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Jun 20, 2023, 7:12:56 AM6/20/23
to DSpace Technical Support
Hello Nicolas, Mohammad,
I have the same problem, this error: No _links section found..
after creating a new certificate, the browser shows this error in the console.
Could you tell me how it was solved.

Thanks a lot
Marwa

Nicolas Battaglia

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Jun 21, 2023, 10:41:11 AM6/21/23
to Marwa Saada, DSpace Technical Support
Hi Marwa

i just add intermediate cert file (i my case, from GoDaddy)


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