Archival HTTP redirection retrieval policies

AlSum, Ahmed; Nelson, Michael L.; Sanderson, Robert; Sompel, Herbert Van de

doi:10.1145/2487788.2488117

Cited by 3 publications

(3 citation statements)

References 25 publications

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“…However, we cannot be sure until we dereference the URI-M and check its response headers for the values in rel="original" and Memento-Datetime. While it is unlikely that the IA will deceive us, the URI-M may redirect to another URI-M with a different Memento-Datetime, or in the case of an archived HTTP redirection, the URI-M might end up at an altogether different URI-R [3]. Furthermore, some archives issue URI-Ms without semantics -for example these URI-Ms are all mementos for google.com but neither this nor the Memento-Datetime can be ascertained without dereferencing: webcitation.org/query?id=1398456230796350, archive.is/sz8b9, and perma.cc/H3YY-BQN5.…”

Section: Opacity Of Uri-msmentioning

confidence: 99%

“…With archives that implement Memento, the Accept-Datetime header instructs the archive to return the originally archived status code (Section 6.1). AlSum et al [3] analyzed memento redirection patterns relating to HTTP redirects to supply the user with the correct memento when a redirect is encountered in the archives. They introduced the notion of "URI stability" to give a quantitative measure of the presence of HTTP 3XX status codes that result when URI-Ms in TimeMaps are dereferenced.…”

Section: Related Workmentioning

confidence: 99%

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Impact of URI Canonicalization on Memento Count

Kelly¹,

Alkwai²,

Nelson³

et al. 2017

2017 ACM/IEEE Joint Conference on Digital Libraries (JCDL)

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Quantifying the captures of a URI over time is useful for researchers to identify the extent to which a Web page has been archived. Memento TimeMaps provide a format to list mementos (URI-Ms) for captures along with brief metadata, like Memento-Datetime, for each URI-M. However, when some URI-Ms are dereferenced, they simply provide a redirect to a different URI-M (instead of a unique representation at the datetime), often also present in the TimeMap. This infers that confidently obtaining an accurate count quantifying the number of non-forwarding captures for a URI-R is not possible using a TimeMap alone and that the magnitude of a TimeMap is not equivalent to the number of representations it identifies. In this work we discuss this particular phenomena in depth. We also perform a breakdown of the dynamics of counting mementos for a particular URI-R (google.com) and quantify the prevalence of the various canonicalization patterns that exacerbate attempts at counting using only a TimeMap. For google.com we found that 84.9% of the URI-Ms result in an HTTP redirect when dereferenced. We expand on and apply this metric to TimeMaps for seven other URI-Rs of large Web sites and thirteen academic institutions. Using a ratio metric DI for the number of URI-Ms without redirects to those requiring a redirect when dereferenced, five of the eight large web sites' and two of the thirteen academic institutions' TimeMaps had a ratio of ratio less than one, indicating that more than half of the URI-Ms in these TimeMaps result in redirects when dereferenced.

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Section: Opacity Of Uri-msmentioning

confidence: 99%

Section: Related Workmentioning

confidence: 99%

Impact of URI Canonicalization on Memento Count

Kelly¹,

Alkwai²,

Nelson³

et al. 2017

2017 ACM/IEEE Joint Conference on Digital Libraries (JCDL)

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“…The research conducted so far has accepted the lists of URI-Ms in timemaps as ground truth; however, timemaps only tell part of the story. For example, a URI-M listed in a timemap may redirect to another with a different Memento-Datetime [5]. Redirections are likely to impact temporal coherence, which could change the coherence state of some eURI-Ms. Redirection could also be an indication of duplication; however, timemaps and archives provide no indication of cause for redirections, so we cannot be sure.…”

Section: Redirection and Missing Mementosmentioning

confidence: 99%

Only One Out of Five Archived Web Pages Existed as Presented

Ainsworth

Nelson

Sompel

2015

Proceedings of the 26th ACM Conference on Hypertext &Amp; Social Media - HT '15

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When a user retrieves a page from a web archive, the page is marked with the acquisition datetime of the root resource, which effectively asserts "this is how the page looked at a that datetime." However, embedded resources, such as images, are often archived at different datetimes than the main page. The presentation appears temporally coherent, but is composed from resources acquired over a wide range of datetimes. We examine the completeness and temporal coherence of composite archived resources (composite mementos) under two selection heuristics. The completeness and temporal coherence achieved using a single archive was compared to the results achieved using multiple archives. We found that at most 38.7% of composite mementos are both temporally coherent and that at most only 17.9% (roughly 1 in 5) are temporally coherent and 100% complete. Using multiple archives increases mean completeness by 3.1-4.1% but also reduces temporal coherence.

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