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Luke sh commented on NUTCH-1997: -------------------------------- Thanks a lot [~gostep], let me test it out and will let you know the result, thanks > Add CBOR "magic header" to CommonCrawlDataDumper output > ------------------------------------------------------- > > Key: NUTCH-1997 > URL: https://issues.apache.org/jira/browse/NUTCH-1997 > Project: Nutch > Issue Type: Improvement > Components: tool > Reporter: Giuseppe Totaro > Priority: Minor > Attachments: NUTCH-1997.patch > > > For each file extracted from Nutch crawled data, {{CommonCrawlDataDumper}} > wraps a single string value, representing the JSON text, into CBOR. > For instance, using the Unix {{hexdump}} tool, we can see that, as expected, > the first byte of all files is "0x7F" (the first three bits are "011", that > is the major type for strings, and the following 5 bits are "11010", meaning > a uint32_t encodes the length of following text), and the following 4 bytes > (single-precision float) encodes the right length of file (as described in > [RFC7049|http://tools.ietf.org/html/rfc7049]). Therefore, a CBOR tag is > currently included into the file (a list of cbor tags is available > [here|https://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml]). > In order to add support for CBOR detection using Apache Tika (as described in > [TIKA-1610|https://issues.apache.org/jira/browse/TIKA-1610]), it would be > great if {{CommonCrawlDataDumper}} tool is able to add the self-describing > CBOR "magic header" ([Tag > 55799|http://tools.ietf.org/html/rfc7049#section-2.4.5]) to CBOR-encoded > output files. > Thanks a lot [~Lukeliush] for this great research. Thanks [~chrismattmann] > for supporting me on this work. -- This message was sent by Atlassian JIRA (v6.3.4#6332)