@ardianp-google could you sketch a bit to illustrate what you are thinking?

Are you imagining some named template(s), not unlike how size groups are defined, and then a renderURL could be specified as some combination of a) template key and b) a macro k/v map? Chrome would need to canonicalize this prior to calculating k-anon. Do you envision Chrome merging the identifiers into the template so the seller can score it?

"ads": [
    {
      "renderURL": "https://tdsf.doubleclick.net/td/adfetch/gda?adg_id=140544969557&cr_id=683341607979&cv_id=0&format=${AD_WIDTH}x${AD_HEIGHT}&rds=${RENDER_DATA}",
      "metadata": ...
    }
]

Are you envisioning something like:

"renderURLTemplates": {
    "template1":"https://tdsf.doubleclick.net/td/adfetch/gda?adg_id=${A}&cr_id=${B}&cv_id=${C}&format=${AD_WIDTH}x${AD_HEIGHT}&rds=${RENDER_DATA}"
},

"ads": [
    /* "legacy" renderURL */
    {
        "renderURL": "https://tdsf.doubleclick.net/td/adfetch/gda?adg_id=140544969557&cr_id=683341607979&cv_id=0&format=${AD_WIDTH}x${AD_HEIGHT}&rds=${RENDER_DATA}",
        "metadata": ...
    },
    /* "compressed" renderURL */
    {
        "renderURL": {"template1": {"A":140544969557, "B":683341607979,"C":0}},
        "metadata": ...
    }
]

This seems like an obvious win, look at all this repeating text; it happens not just in renderUrl but also in metadata

this could be adComponents: [], adTokens: { a: 'https://..../gda?', b: '150058563090'}, ads: [{ metadata:"[\"{$b}\"...], renderURL: '{$a}adg_id={$b}&cr_id=.....' etc, or some more valid form of macro definition and expansion

This is something I've been thinking about for a while to reduce interest group sizes. I imagined instead of:

joinAdInterestGroup({ads: [{renderURL: 'https://www.example-dsp.com/ads?ad_id=123456&ad2_id=987654', ...},
                           {renderURL: 'https://www.example-dsp.com/ads?ad_id=234567&ad2_id=876543', ...},
                           {renderURL: 'https://www.example-dsp.com/ads?ad_id=345678&ad2_id=765432', ...}],

I imagined a templated version like:

joinAdInterestGroup({ad_template: 'https://www.example-dsp.com/ads?ad_id=${1}&ad2_id=${2}',
                     ads: [{templatedRenderURL: ['123456', '987654'], ...},
                           {templatedRenderURL: ['234567', '876543'], ...},
                           {templatedRenderURL: ['345678', '765432'], ...}],

Are you imagining some named template(s), not unlike how size groups are defined, and then a renderURL could be specified as some combination of a) template key and b) a macro k/v map?

Yes, I think that's what I'm thinking.

Chrome would need to canonicalize this prior to calculating k-anon. Do you envision Chrome merging the identifiers into the template so the seller can score it?

Yes, I imagine the browser would only use the unexpanded/compresssed form when stored.

Yes, positional (tokens in an array) is slimmer. And it may be the case that a DSP would only need a single template, as in your sketch, though I'm sure there will be some that need flexibility due to various systems or whatever.

Is this what you are also thinking @ardianp-google?

I imagine something closer to what @JensenPaul's proposed, and that's sufficient for our needs. Though it's also a valid point that a more expressive language could be needed to cater more complicated systems.

I imagine something closer to what @JensenPaul's proposed, and that's sufficient for our needs. Though it's also a valid point that a more expressive language could be needed to cater more complicated systems.

This may suffice in today's PA that only does banners. A single renderURL template may be restrictive once PS handles newfangled media like video or native.

@JensenPaul , assuming a single URL template per IG, here's another take (changed to camel case).

"adTemplate": "https://www.example-dsp.com/ads?ad_id=${1}&ad2_id=${2}&cv_id=${3}&format=${AD_WIDTH}x${AD_HEIGHT}&rds=${RENDER_DATA}",

"ads": [
    /* "legacy" renderURL */
    {
        "renderURL": "https://tdsf.doubleclick.net/td/adfetch/gda?adg_id=140544969557&cr_id=683341607979&cv_id=0&format=${AD_WIDTH}x${AD_HEIGHT}&rds=${RENDER_DATA}",
        "sizeGroup": "mySizeGroup",
        "metadata": {...},
    },
    /* "compressed" renderURL */
    {
        "templatedRenderURL": ['140544969557', '683341607979', '0'],
        "sizeGroup": "mySizeGroup",
        "metadata": {...},
    }
]

When bidding with a templated creative, does the bidder submit the tokens array as render.url?

      return {         
            bid: 1.25,
            
            render: {
               'url': renderURL,   /* this should be a reference to the ad's templatedRenderURL array? */
               'width': '300', 
               'height': '250'
            },
            
            allowComponentAuction: true
        };

If we do this, we may need some sort of abuse protection, since simple substitution into a shared string potentially allows O(n^2) blowup, for strings that don't even need to be received from a server, but could instead be generated by Javascript.

Edit: I'd think the main effect of abuse would be to bring the browser to a crawl or crash it as it extracts URLs, if it keeps them all in memory. It wouldn't swamp the k-anon server (since we only send hashes there).