I am attempting to create a database of Digital Object Identifier (DOI) found on the internet.
By manually searching the CommonCrawl Index Server manually I have obtained some promising results.
However I wish to develop a programmatic solution.
This may result in my process only requiring to read the index files and not the underlying WARC data files.
The manual steps I wish to automate are these:-
1). for each CommonCrawl Currently available index collection(s):
2). I search ... "Search a url in this collection: (Wildcards -- Prefix: http://example.com/* Domain: *.example.com) " e.g. link.springer.com/*
3). this returns almost 6MB of json data that contains approx 22K unique DOIs.
How can I browse all available CommonCrawl indexes instead of searching for specific URLs?
From reading the API documentation for CommonCrawl I cannot see how I can browse all the indexes to extract all DOIs for all domains.
UPDATE
I found this example java code https://github.com/Smerity/cc-warc-examples/blob/master/src/org/commoncrawl/examples/S3ReaderTest.java
that shows how to access a common crawl dataset.
However when I run it I receive this exception
"main" org.jets3t.service.S3ServiceException: Service Error Message. -- ResponseCode: 404, ResponseStatus: Not Found, XML Error Message: <?xml version="1.0" encoding="UTF-8"?><Error><Code>NoSuchKey</Code><Message>The specified key does not exist.</Message><Key>common-crawl/crawl-data/CC-MAIN-2016-26/segments/1466783399106.96/warc/CC-MAIN-20160624154959-00160-ip-10-164-35-72.ec2.internal.warc.gz</Key><RequestId>1FEFC14E80D871DE</RequestId><HostId>yfmhUAwkdNeGpYPWZHakSyb5rdtrlSMjuT5tVW/Pfu440jvufLuuTBPC25vIPDr4Cd5x4ruSCHQ=</HostId></Error>
In fact every file I try to read results in the same error. Why is that?
what is the correct common crawl uri's for their datasets?
To get the example code to work replace lines 24 and 25 with:
String fn = "crawl-data/CC-MAIN-2013-48/segments/1386163035819/warc/CC-MAIN-20131204131715-00000-ip-10-33-133-15.ec2.internal.warc.gz";
S3Object f = s3s.getObject("commoncrawl", fn, null, null, null, null, null, null);
Also note that the commoncrawl group have an updated example.