the theory and practice of website archivability

The Theory and Practice of Website

Archivability

Vangelis Banos1, Yunhyong Kim2, Seamus Ross2, Yannis Manolopoulos1

20 SEPT 2013WEB ARCHIVING MEETING,

INNSBRUCK, AUSTRIA

1Department of Informatics, Aristotle University, Thessaloniki , Greece2University of Glasgow, United Kingdom

FROM CLEAR TO ARCHIVEREADY.COM

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Table of Contents1. Problem definition,

2. CLEAR: A Credible Live Method to Evaluate Website Archivability,

3. Demo: http://archiveready.com/,

4. Future Work.

Problem definition• Web content acquisition is a critical step in

the process of web archiving,• Web bots face increasing difficulties in

harvesting websites,

• After web harvesting, archive administrators review manually the content and endorse or reject the harvested material,

• Key Problem: Web harvesting is automated while Quality Assurance (QA) is manual.

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WebsiteArchivability ?

What is

Website Archivability captures the core aspects of a website crucial in diagnosing whether it has

the potentiality to be archived with completeness and accuracy.

Attention! it must not be confused with website dependability, reliability, availability, safety, security, survivability, maintainability.

CLEAR: A Credible Live Method to Evaluate Website Archivability• An approach to producing a credible on-the-fly

measurement of Website Archivability, by:• Using standard HTTP to get website elements,• Evaluating information such as file types, content

encoding and transfer errors,• Combining this information with an evaluation of the

website's compliance with recognised practices in digital curation,• Using adopted standards, validating formats,

assigning metadata• Calculating Website Archivability Score (0 – 100%)

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Accessibility

Cohesion

StandardsCompliance Performance

Metadata

CLEAR: A Credible Live Method to Evaluate Website Archivability

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Website attributes evaluated using CLEAR

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C L E A R• The method can be summarised as follows:

1. Perform specific Evaluations on Website Attributes,

2. In order to calculate each Archivability Facet’s score,• Scores range from (0 – 100%),• Not all evaluations are equal, if an important

evaluation fails, score = 0, if a minor evaluation fails, score = 50%

3. Producing the final Website Archivability as the sum all Facets’ scores.

Accessibility

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Are web archiving crawlers able to discover all content using standard protocols and best practices?

Accessibility evaluation

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Facet Evaluation Rating Total

Accessibility

No RSS feed 50%

50%No robots.txt 50%

No sitemap.xml 0%

6 links, all valid 100%

http://ipres2013.ist.utl.pt/ Website Archivability evaluation on 23rd April 2013

Cohesion

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• Dependencies are a great issue in digital curation.

• If a website is dispersed across different web locations (images, javascripts, CSS, CDNs, etc), the acquisition and ingest is likely to risk suffering if one or more web locations fail on change.

• Web bots may have issues accessing a lot of different web locations due to configuration issues.

Cohesion evaluation

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Facet Evaluation Rating Total

Cohesion

1 external and no internal scripts 0%

70%

4 local and 1 external images 80%

No proprietary (Quicktime & Flash) files

100%

1 local CSS file 100%

http://ipres2013.ist.utl.pt/ Website Archivability evaluation on 23rd April 2013

Metadata

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• Metadata are necessary for digital curation and archiving.

• Lack of metadata impairs the ability to manage, organise, retrieve and interact with content.

• Web content metadata may be:• Syntactic: (e.g. content encoding, character set)• Semantic: (e.g. description, keywords, dates)• Pragmatic: (e.g. FOAF, RDF, Dublin Core)

Metadata evaluation1. What is it2. How is it calculated

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Facet Evaluation Rating Total

Metadata

Meta description found 100%

87%HTTP Content type 100%

HTTP Page expiration not found 50%

HTTP Last-modified found 100%

http://ipres2013.ist.utl.pt/ Website Archivability evaluation on 23rd April 2013

Performance

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• Calculate the average network response time for all website content.

• The throughput of web spider data acquisition affects the number and complexity of the web sources it can process.

• Performance evaluation:Facet Evaluation Rating Total

Performance Average network response time is 0.546ms

100% 100%

http://ipres2013.ist.utl.pt/ Website Archivability evaluation on 23rd April 2013

Standards Compliance

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• Digital curation best practices recommend that web resources must be represented in known and transparent standards, in order to be preserved.

Standards Compliance evaluation

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Facet Evaluation Rating Total

Standards Compliance

1 Invalid CSS file 0%

87%

Invalid HTML file 0%

Meta description found 100%No HTTP Content encoding 50%HTTP Content Type found 100%HTTP Page expiration found 100%HTTP Last-modified found 100%No Quicktime or Flash objects 100%5 images found and validated with JHOVE 100%

http://ipres2013.ist.utl.pt/ Website Archivability evaluation on 23rd April 2013

iPRES 2013 Website Archivability Evaluation

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Facet Rating Website Archivability

Accessibility 50%

77%Cohesion 70%

Standards Compliance 77%

Metadata 87%

Performance 100%

ArchiveReady.comDemonstration

- Web application implementing CLEAR,

- Web interface & also Web API in JSON,

- Running on Linux, Python, Nginx, Redis, Mysql.

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Impact

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1. Web professionals - evaluate the archivability of their websites in an easy but thorough way, - become aware of web preservation concepts, - embrace preservation-friendly practices.

2. Web archive operators - make informed decisions on archiving websites, - perform large scale website evaluations with ease, - automate web archiving Quality Assurance, - minimise wasted resources on problematic websites.

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Future Work1. Not optimal to treat all Archivability Facets as equal.

2. Evaluating a single website page, based on the assumption that web pages from the same website share the same components and standards. Sampling would be necessary.

3. Certain classes and specific types of errors create lesser or greater obstacles to website acquisition and ingest than others. Differential valuing of error classes and types is necessary.

4. Cross validation with web archive data is under way

THANK YOUVangelis BanosWeb: http://vbanos.gr/Email: vbanos@gmail.com

ANY QUESTIONS?

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The research leading to these results hasreceived funding from the European Commission Framework Programme 7 (FP7), BlogForever project, grant agreement No.269963.