Calling to_string() method on some data

[dandyvica]

Hi @sunng87

Thanks for your amazing work.

Suppose you have a data structure which is mapped to the following JSON:

{
  "name": ".",
  "type": "RRSIG",
  "class": "IN",
  "ttl": 172800,
  "rd_length": 275,
  "rdata": {
    "type_covered": "DNSKEY",
    "algorithm": "RSASHA256",
    "labels": 0,
    "ttl": 172800,
    "sign_expiration": "20250110000000",
    "sign_inception": "20241220000000",
    "name": ".",
    "signature":  "blabla"
  }

The rdata field is a Rust structure for which the to_string() exists. Is it possible to code a helper to call that to_string() method in a template ? The rdata field is not always the same (actually an enum).

Thanks !

[sunng87]

hello @dandyvica , handlebars uses serde_json's Value as internal type system because the original handlebarsjs is based on JavaScript. So it has no access to rdata's to_string when rendering a template. My idea is to implement a custom serde Serializer that serializes rdata as a string field and calls to_string there.

[dandyvica]

@sunng87 Thanks for your answer. I already have such a custom Serializer, but I don't know how to express it in the handlebars template file. Any hint ?

[sunng87]

@dandyvica you can just try {{rdata}} and see output

[dandyvica]

It's weird because in some cases, the to_string() method seems to be called and result is right, other cases just prints out object:

contact.zonetransfer.me. TXT <[Remember to call or email Pippa on +44 123 4567890 or [email protected] when making DNS changes]>
dc-office.zonetransfer.me. A <143.228.181.132>
deadbeef.zonetransfer.me. AAAA <dead:beaf::>
dr.zonetransfer.me. LOC <[object]>
DZC.zonetransfer.me. TXT <[AbCdEfG]>
email.zonetransfer.me. NAPTR <[object]>
email.zonetransfer.me. A <74.125.206.26>
Hello.zonetransfer.me. TXT <[Hi to Josh and all his class]>
home.zonetransfer.me. A <127.0.0.1>
Info.zonetransfer.me. TXT <[ZoneTransfer.me service provided by Robin Wood - [email protected]. See http://digi.ninja/projects/zonetransferme.php for more information.]>
internal.zonetransfer.me. NS <intns1.zonetransfer.me.>
internal.zonetransfer.me. NS <intns2.zonetransfer.me.>
intns1.zonetransfer.me. A <81.4.108.41>
intns2.zonetransfer.me. A <167.88.42.94>
office.zonetransfer.me. A <4.23.39.254>
ipv6actnow.org.zonetransfer.me. AAAA <2001:67c:2e8:11::c100:1332>
owa.zonetransfer.me. A <207.46.197.32>
robinwood.zonetransfer.me. TXT <[Robin Wood]>
rp.zonetransfer.me. RP <[object]>
sip.zonetransfer.me. NAPTR <[object]>
sqli.zonetransfer.me. TXT <[&#x27; or 1&#x3D;1 --]>
sshock.zonetransfer.me. TXT <[() { :]}; echo ShellShocked]>
staging.zonetransfer.me. CNAME <www.sydneyoperahouse.com.>
alltcpportsopen.firewall.test.zonetransfer.me. A <127.0.0.1>

Original template is:

{{#each messages}}
{{#each response.answer}}
{{name}} {{type}} <{{rdata}}>
{{/each}}
{{/each}}

[sunng87]

Do you have other variants of rdata field? When it renders [object] it means it's a json object.