The problem of leuven ezproxy

You get to the publisher site, but access to restricted resources is yet not possible.In that case, you see that the code “…” is not included in the url. This means that the resource is not registered for off campus access. If you think this is in error, you can contact the e-resources department of the KU Leuven library to register this resource for off campus access.If off campus access to the resource is permitted according to the license agreement of the publisher, it will soon be activated by the technical services. You will be informed accordingly.You get the message:  “You don’t have the rights to use the EZproxy of ..”

Only students and staff of an institution can have off campus access to the e-resources the institution pays for. This means that your student registration or contract only allows you to use EZproxy of the institution(s) you below to, and not to the EZproxy of other institutions within the KU Leuven Association.

Exceptionally, it can happen that you also see the above message when trying to use EZproxy of your own institution or organization.  This could mean there is an administrative issue. Please contact the e-resources department of the KU Leuven library ( ) in that case. You can’t find the e-resource you want to consult via Limo:contact the e-resource service of the KU Leuven library( campus access to external sites that don’t belong to the library collection is not possible via EZproxy. Contact the ICTS department of the Leuven ( if you have questions if this causes problems to you.

Proxy Servers with the Google Data

A proxy server is a computer (or service on a computer) that makes requests for a number of client computers on their behalf, typically to external resources. This article is concerned with HTTP proxy servers as HTTP is the protocol used to access the public APIs for Google’s web services. By extension, HTTPS or SSL proxies are also of interest when making HTTP requests that contain sensitive information such as private user data or passwords. Many large companies today use HTTP proxies to control what websites or information employees can view on the internet. Public libraries and schools have also been known to implement proxies for this purpose. There are also a number of publicly available proxy servers that can be used to anonymously access web content.

Potential issues faced when using a proxy server depend on what software is being used and how it is configured. A proxy is considered to be “transparent” if it does not alter the request from the client or the response from the server in any way other than is necessary for proxy identification and authentication. However, a large number of proxy servers do alter either the request or the response in ways that a developer should be aware of. In particular, certain proxies will alter the content-type of the response or strip out HTTP keep-alive headers from being sent to the outside server hosting the resource.

So why would a developer want to use an HTTP or SSL proxy? Generally, there are two reasons for this: it is required by some corporate infrastructure, or, the developer wishes to debug an application that uses a web service. The first reason is entirely unavoidable if the rules for the network the developer is working on prohibit non-proxied web or SSL connections to external websites. The latter reason is reported frequently in our support forums by developers trying to troubleshoot issues when dealing with a Google web service. There are special-purpose “debugging” proxies such as Fiddler and Charles that are geared towards this exact situation. For more information on this use of a proxy server, you may want to read our article On the Wire: Tools for API Developers.

For some applications, adding in proxy server support can be difficult. Fortunately, most of the client libraries for the Google Data API can be made to work with an HTTP proxy server after some slight code modifications. This article is intended to serve as a starting point for a developer who would like to use a proxy server for the web requests made by their application.


Using an HTTP proxy with the Java client library is easy thanks to Sun’s use of system properties to manage connection settings.

For example, if your corporate proxy server were running on “”, on port 3128, you could add the following to your code before creating a service object for Google Calendar, Google Spreadsheets, etc.

System.setProperty("http.proxyHost", "");
System.setProperty("http.proxyPort", "3128");

Alternatively, this can be done on the command line when starting your servlet environment:

java -Dhttp.proxyPort=3128

With more recent versions of the JSSE package, this can be extended to SSL proxies as well. If the same proxy server in the previous example was running an SSL proxy on port 3129, the necessary code would be:

System.setProperty("https.proxyHost", "");
System.setProperty("https.proxyPort", "3129");

This can also be done from the command line in the same fashion as with the HTTP proxy.

Sometimes, you might need to provide credentials to a proxy server in order to use it. Usually, they are submitted using a base64 hash included in an HTTP header, as follows:

String encoded = new String(Base64.encodeBase64(new String("username:password").getBytes()));
String base64encodedCredentials = "Basic " + encoded;
myService.getRequestFactory().setPrivateHeader("Proxy-Authorization", base64encodedCredentials);

Note that the above code uses the Apache Commons Codec package in order to do the base64 encoding necessary. You’ll have to import the org.apache.commons.codec.binary.Base64 class in order to run the above code.


To use an HTTP proxy with the .NET client library is not as trivial as with the Java client, but it can be accomplished in a similar way when creating the service object for a particular product.

For example, we might want to use a proxy to interact with the Google Calendar service:

using System.Net;

CalendarService service = new CalendarService("CalendarSampleApp");
query.Uri = new Uri(calendarURI);
GDataRequestFactory requestFactory = (GDataRequestFactory) service.RequestFactory;
IWebProxy iProxy = WebRequest.DefaultWebProxy;
WebProxy myProxy = new WebProxy(iProxy.GetProxy(query.Uri));
// potentially, setup credentials on the proxy here
myProxy.Credentials = CredentialCache.DefaultCredentials;
myProxy.UseDefaultCredentials = true;
requestFactory.Proxy = myProxy;

This should detect the necessary proxy from your Internet connection settings–a nice feature of the .NET library. However, if you do not trust it to discover the proxy properly, you can also set it by changing the code to:

using System.Net;

CalendarService service = new CalendarService("CalendarSampleApp");
GDataRequestFactory requestFactory = (GDataRequestFactory) service.RequestFactory;
WebProxy myProxy = new WebProxy("",true);
// potentially, setup credentials on the proxy here
myProxy.Credentials = CredentialCache.DefaultCredentials;
myProxy.UseDefaultCredentials = true;
requestFactory.Proxy = myProxy;


This article has discussed how to have some of the Google Data API client libraries work with an HTTP proxy server. Developers working behind a proxy server mandated by network policy can still use these libraries. Developers can also employ a proxy server to help debug their code by having the proxy server record the contents of HTTP requests and responses being sent to and from a Google web service. There are more advanced use cases of a proxy server and other client libraries not covered by this tutorial. Developers needing additional help are encouraged to participate in our public support groups linked below.

The proxy bookmarklet tips

First make sure you installed the proxy bookmarklet correctly and you have used it on the correct page ie vendor/publisher pages not NUS Libraries’ page.

If you were actually using Google Scholar or PubMed with the proxy bookmarklet, you may wish to try the following new

methods to check for full-text access via the new “Find it! @ NUS Libraries” function.

  • Google Scholar with Find it! @ NUS Libraries
  • PubMed  with Find it! @ NUS Libraries

If you get an error or if there is no error and you still cannot get the full text, you will need to do to check to see if the library actually has access.

 If that still doesn’t work you will have to  check the library catalogue by journal name e.g (Journal of Sociology) to see if there is access via another online source or if a print copy is available to confirm definitely if the library access.

Want to understand why the proxy bookmarklet doesn’t work? Read on.

1) Library just does not have access to the item through that vendor/publisher page

The same journal article can be available on different multiple sites, we may actually have the article full-text online in another, publisher, aggregator or subscription agent site but not on the current page you are using the proxy bookmarklet on.

You may get the following error if it is a site we do not have access to- “URL Not Configured. You are trying to access a resource that the NUS Library Proxy Service has not been configured to work with.”

Do note that even if we have access to a site eg, we may not have access to every item on the platform & you may still be asked to pay.

For example NUS Libraries does not provide access to full text articles from , but many of the articles there can usually be found another site that the library does have access to such as OVIDSP (depends on journal title).

Also the proxy bookmarklet works for source titles that are within the NUS Libraries subscription. However, NUS Libraries does not have subscription to every online article, for every year or  for every vendor/platform (e.g We do not subscribe to every article on Taylor & Francis platform).

Sometimes NUS Libraries just doesn’t subscribe to that article online, but we may have the print version.

2) The database/platform does not properly support this method of access

Currently, we are aware that among others, the proxy bookmarklet may not properly work on articles from JSTOR , IEEE  Refer to workarounds.

How to Find Chinese Journal

What follows is the recommended method to establish if NUS Libraries has access to a known article, all other methods including using Articles Tab, or searching LINC+ then selecting articles or searching using FindMore@NUSL is not guaranteed to work. If you follow these instructions and you still can’t find it, it is very likely we just don’t have access to it, if so and this article is critical to your research, you might be able to request the library purchase it via Document Delivery Service.

If you are given a citation, identify for the journal article

a) journal title article is in – e.g “Quarterly Journal of Economics”

b) year of publication – e.g 2011

c) vol/issue article it is in – e.g 126(4)

and not just the article title e.g. “Cash or condition ? evidence from a cash transfer experiment.”

Don’t know what the journal title is? Search Google or Google Scholar by article title for full reference.

1. If you only have an abbreviated journal title and do not know the complete title, check Journal abbreviations for the complete title. E.g. Appl Math Optim.

Some listings you can try to check Journal Abbreviations include JAS: Journal Abbreviation Sources, Genamics JournalSeek , UlrichsWeb, NLM List of Serials Indexed for Online Users, Canada Institute for Scientific and Technical Information (CISTI) , Singapore – Legal Abbreviations compiled by the C J Koh Law Library or just by doing a Google search.

2. Do a search in LINC for the journal to see if the required journal issue is available either in print or in online version. At the search box, type in the complete title or as much of the beginning of the title. E.g. Applied mathematics and optimization.

If there are too many results you might want to restrict the search to the Journals collection.

3. If there is no exact hit, browse the titles near what you have typed. If the title you want is not there, click on Search As Words to do a keyword search.

4. If the journal is available in the library, you can see the full record. Depending on the journal availability not all sections will be shown.

a) check the online versions to see if the issue you need is available

b) click on latest received to see the newest print issues received (these are generally in the current journal sections and cannot be borrowed out).

c) check the OLDER issues (bound volumes) available in the library. By default only a maximum of 10 bound journals are shown. Click on View additional copies or search for a specific volume/copy  to see all print issues available.

All the bound volumes available in the NUS Libraries is then listed. Bound volumes may be kept in Bound Journals or Closed Stacks. See How do I request a closed stack item?

Do note that journals titles tend to change fairly frequently , so you may have to check successor or preceding journals by clicking on “Continued By” or “Continues”.

5. If either the journal or the issue is not available in NUS Libraries, you may also want to do a Google or Google Scholar search by article title (with quotes around the search if necessary) to see if the article is available free online.  If the link brings you to a page that requires payment, you can try the proxy bookmarklet to see if you have access.

What is a proxy bookmarklet

unduhan-24The proxy bookmarklet automatically inserts the NUS Libraries proxy stem “” into the URL of an article link in your browser. Once you have  successfully installed the bookmarklet once, you can access full-texts of journal articles that are within the NUS Libraries’ subscription by clicking on the bookmarklet on any page that requires you to pay. This will attempt to access the resource via NUS Libraries’ sunscription.

Please note that this method does not work 100% reliably on all databases and sources (See exceptions). An article may also be available in multiple locations, aggregators.

Alternatively, if you are using Google Scholar or PubMed the following NEW method of accessing full text via NUS Subscriptions will avoid some of the problems listed above.

The proxy bookmarklet allows you to directly access full text of E-resources via the subscription of NUS.  The video below shows how to install and use proxy bookmarklet to access full text of a reference obtained from a Google Scholar  search. Please note that this will work for most but not all sites.

Why should you use the proxy bookmarklet?

Scenario 1:
You searched Google and found some relevant titles in the list of search results.  However, when you click on an article link, you are redirected  to a vendor or publisher’s site where you will be asked to pay for the full-text.

Scenario 2:
You receive direct links to online articles from a friend and after reading the abstract, you want to read the full-texts.  Similarly, when you click on the article links via email,blogs, twitter and you are directed to the publisher or vendor site where you are required to log in or pay to view full-texts.

Solution: Proxy Bookmarklet
Note that in the above scenarios, you are not coming directly from the NUS Libraries portal and hence the publisher/vendor site does not know that you have access via subscriptions from NUS.

You can of course, go back to our library portal and search the database or journal from there, but there’s a faster way to authenticate and access the article directly. This involves adding the proxy stem to the URL. One way of doing so is to use the proxy bookmarklet.

Easy to access the full text of journal tips

Google Scholar is a good resource to use for searching but the main drawback is that it is difficult to

a) check if you have access to the article displayed online via NUS Libraries subscriptions

b) get access even if the article is accessible via NUS Libraries subscriptions as the publisher is unaware you are from NUS, so when you click through Google Scholar into the article you will be asked to pay.

There are two main ways to help solve these two issues though they are not fool-proof as Google Scholar is a free tool.

Firstly, you can use the older proxy bookmarklet method, but this may not always work.

The second method, involves using the build-in Google Scholar’s Library Links  Programme which NUS Libraries is now registered with.

If you add NUS Libraries to your settings (see section below), Google Scholar will try to identify what articles you have access via our subscriptions and show a Find it! @NUS Libraries link.

Alternatively you can bookmark the following special google scholar link and search from there, which will do the same.

Here’s how you add this to your settings

1. At Google Scholar, click on Settings at the top right corner. (Note Google, often changes the position of this)

2. Click on Library Links on the left.

3. Search for nus and select National University of Singapore – Findit! @NUS Libraries

4. Click Save.

If you have logged-in using your Google account already, this setting will be tied to it, if not it will be tied to a cookie on your PC that may be cleared depending on your settings. See this for details.

Text of journal from PubMed to access tips

PubMed is a free citation database that contain items from various sources including Medline. While PubMed might link to full-text, some of which is free in PMC or other open access or free titles, most items require a subscription and not all such items can be accessed via NUS Libraries subscription.

So how does one identify what items can be accessed via NUS Libraries subscriptions?

This is a normal URL that you can bookmark on desktops or iPads (but see the following note). You can also access it via the Library portal, catalogue etc.

Alternatively, if you have your own My NCBI account you can also change your settings to support this.

For more details watch the following video from NLM

Once this is done, you can do the following.

If you want to see results that only can be accessed via NUS Libraries’ holding, after running a search, click on the filter on the right, National University of Singapore Libraries.

This will restrict results to just items PubMed thinks we have access to via NUS Libraries. The number in parentheses indicates the number of results.

Please note that while this will include some free and open access articles that we have included in our holdings (you can restrict to this by clicking on Free Full text available filter on the left), this won’t usually overlap 100% with PubMed’s Free full text filter (all articles known to be free via PMC or publisher by PubMed) alone as we don’t include all free journals in our holdings.

It may also miss some of the most recent articles just posted that are [PubMed – in process] , or [PubMed – as supplied by publisher]

Alternatively, click on an article you are interested in and look for a button that says “Find it! @NUSLibraries”

The same button can be seen at the bottom of each record, if the Display setting is set to Format — Abstract.

In either case, clicking on the button will usually bring you directly to full-text, though occasionally it may drop you into the 360link results page (instructions on what to do), or in the worse case scenario, the page in the bottom frame fails to load in which case you should click on “Get additional resources”.

Sometimes you will see other buttons, if it is free from publisher as below. Typically such buttons will have the word “Free” or “Open Access”.