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Advanced Archive-It Application Training:

Crawl Scoping

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Agenda

• Basic Crawl Scoping and Seed Types• What to look for in your reports• How to Change your Crawl Scope– Crawl Limits– Expand scope– Host rules– Actionable Host report

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Archive-It Crawling Scope

• Scope: How to specify what you want to archive

• in scope URLs will be archived• out of scope URLs are not archived.

• The scope of a crawl is determined by • the seed URLs added to a collection • by any scoping rules specified for your

collection

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Archive-It Crawling Scope

• The crawler will start with your seed URL and follow links within your seed site to archive pages

• Only links associated with your seeds will be archived• All embedded content on an in scope page is captured

Example seed: www.archive.org/• Link: www.archive.org/about.html is in scope • Link: www.ca.gov is NOT in scope• Embedded image: www.ala.org/logo.jpg is in scope

Archive-It Crawling Scope

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• Seed URLs can limit the crawl to a single directory of a site.

• ex: www.archive.org/about/

* a / at the end of your url can have a big effect on scope

* Parts of the site not included in your seed directory will NOT be archived

Example seed: www.archive.org/about/

Link: www.archive.org/webarchive.html NOT in scope

Example seed: www.archive.org/about

Link: www.archive.org/webarchive.html IS in scope

Archive-It Crawling Scope

• Sub-domains are divisions of a larger site named to the left of the host name (ex. crawler.archive.org)

• Sub-domains of seed URLs are NOT automatically in scope

• To crawl sub-domains, either:• Add individual sub-domains as separate seed URLs• Or add an ‘Expand Scope’ rule to allow all or specific

sub-domainsExample seed: www.archive.org– Link: crawler.archive.org NOT in scopeExample seed: archive.org• Link: : crawler.archive.org IS in scope 6

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Seed Types

Default

– Used in majority of seeds and the universal setting for most crawls. Will capture all links that are in scope.

Crawl One Page Only

– Capture just your seed URL and embedded content

RSS/News Feed

– Capture any linked pages from your seed URL as one page only

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Analyzing Crawl Scope

• How to analyze the scope of your crawls:– Run a test crawl on new collections or seeds– Review reports of test crawl (or for existing crawl,

review reports of actual crawl)– Based on the reports, you will be able to add the

appropriate scoping rules– It is a good idea to run a test crawl with your scoping

rules in to ensure they are correct.– Note: Running test crawls is just the first step. You

may need to run additional tests to perfect scoping rules.

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Hosts Report

• Are there numbers in the “Queued” or “Robots.txt Blocked” column?– Check the URL lists to see if you want to capture these URLs or not

• Are there hosts with fewer or more archived URLs than you expected?– Fewer: Are any expected URLs “Out of Scope”?– More: Are there parts of the site or specific URLs you want to block?

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Common Reasons to Limit Crawl Scope

• Crawler traps (ex: calendars)• “Duplicate” URLs (ex: print version URLs)• If there are certain areas of the site you do not

care about or do not want to archive• If you just want a snapshot of the site, and

don’t necessarily want to crawl it to completion

• If you only want to capture one page of a site

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Modify Crawl Scope

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Crawl Limits

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2 Different Types of Rules

Host Constraints– Ignore Robots.txt– Block a host– Limit the kinds of URLs from a specific host

-by text match-by Regular Expression

Expand Scope– Include URLs in a crawl that would not be in scope by default

-by text match-by regular expression-by SURT

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Host Constraints

• Specific to a host

http://www.facebook.com/archiveitorg is a URL

www.facebook.com is the HOST

facebook.com is a host, and applies to all subdomains, including photos.facebook.com

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Adding Host Constraints

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Adding Host Constraints

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Adding Host Constraints

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Adding Host Constraints

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Actionable Hosts Report

• Available in 5.0 Reports: Allows you to quickly add and review rules that were in place for specific hosts, as well as run a patch crawl for URLs blocked by Robots.txt.

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Actionable Hosts Report

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Actionable Hosts Report

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Expand Crawl Scope

• How do you know you need to expand your scope?– Review the ‘Out of Scope’ column in the Hosts

Report.– If in clicking around your archived site you find

‘Not in Archive’ trends that could be addressed by an expand scope rule

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Expand Crawl Scope

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Expand Crawl Scope

– Include all (or only specific) subdomains– Include certain parts of the site that may not have been

included based on the seed URL• Ex: seed URL is:

http://mgahouse.maryland.gov/But you also want to archive pages such as:• http://files.maryland.gov/House/report.pdf

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Expand Crawl Scope

Solution: Add an expand scope rule to include URLs that contain:“files.maryland.gov”

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Expand Crawl Scope

WARNINGExpanding scope is a powerful tool, and the more specific the better. Expand scope rules do not help the crawler discover URLs.

Common mistake scenario: I’m responsible for archiving amazinguniversity.edu, so I’m going to create an expand scope rule to include any URL with amazinguniversity.edu.

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Play it safe

1. Run Test Crawls

1. Deactivate Rules when appropriate.

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Q&A