Introduction

Unfortunately, it is necessary to protect the system from automated attacks that manipulate the search-result navigation, creating excessive and unnecessary system load and causing stability issues.

In order to protect the system from attacks of this sort while still allowing legitimate users to continue browsing search results, unauthenticated (guest) users are only allowed to access the first 500 results in the results list. When a guest user attempts to navigate to a page in which results beyond 500 would be displayed, they are prompted to either sign into Primo VE or to verify via reCaptcha that they are human (depending on whether the institution has set up reCaptcha or not – see Configuring reCaptcha for Primo VE).

Signed-in users enjoy a full browsing experience, with no limitations on the number of results that can be viewed (except for searches initiated through the API; see Primo Search API, below). To provide the best experience for guest users, especially at institutions with high guest-user traffic, we recommend enabling reCaptcha. This allows users to continue browsing large result sets without interruption after verification.

The following diagram illustrates how Primo VE handles the situation when a user attempts to navigate to a page of search results that includes those with an offset from the first result of more than 500:

Three-Layered Solution

This solution is built on a three-layered approach that adapts based on two factors: the patron's authentication state (guest vs. signed-in) and whether the institution has enabled reCaptcha.

Layer 1 — Deep Link Handling
When any user (guest or signed-in) arrives at a search result via a deep link or permalink, the system automatically resets the offset to page 1. The search context — including any active facets — is preserved. This also applies to Collection pages that use a Load more items link rather than standard pagination for advancing from page to page in the results.

Layer 2 — reCaptcha
Institutions can optionally enable reCaptcha (see Configuring reCaptcha for Primo VE). When it is enabled, reCaptcha is triggered for guest users who reach the offset-500 threshold. In this case, a reCaptcha Verify pop-up (e.g., Verify you are human) opens instead of a sign-in prompt. If the user successfully completes the reCaptcha requirement, they can continue viewing additional results beyond the 500-offset limit.

Layer 3 — Sign-In with Pagination Reset
If reCaptcha is not enabled, guest users who reach the offset-500 limit are prompted to sign in. Upon signing in, the result set resets to page 1 and any prior offset is discarded. This is necessary in order to ensure a consistent post-authentication experience.

Institutions with No Sign-In Option

In institutions that do not support signing-in for patrons, so that all users are guests at all times, the handling is similar:

• If the institution has enabled reCaptcha, when the user reaches the offset-500 limit, reCaptcha is triggered, as described above.
• If the institution has not enabled reCaptcha, when the user reaches the offset-500 limit, an Only a limited number of results are available message pops up. When the user closes the message, the last page of results remains open.

Primo Search API

The maximum number of retrievable search results via the Primo Search API is limited for both authenticated users and guest users, as follows:

• Authenticated users – 2000 results
• Guest users – 500 results

Applications that rely on deep result pagination should review their integrations and adjust accordingly. For additional information, see Primo Search in the Developer Network.

Label Customization

The following labels used for this feature can be customized (Discovery > Display Configuration > Labels):

• nde.login.verify_reCaptcha – Verify you are human
• nde.login.max_results_guest – Maximum results displayed for a guest user
• nde.login.continue_search – Guest limit reached
• nde.login.continue_search_subtitle – Sign in to continue
• nde.login.no_signin_available – Only a limited number of results are available