Breadcrumbs not updated when users updating area name

[vnugent]

When an area is created, we also generate its bread crumbs data in pathTokens field. However, when we update an area's name, we don't update pathTokens.

To do:

• Case 1: The area has no child areas. Simply update pathTokens when we update area's name.
• Case2: The area has child areas. We need to update all of its children's pathTokens

[CocoisBuggy]

I can fix this but I just want to make absolutely sure we don't want to resolve this at query time rather than at mod time?

We chatted about reads being far more frequent than writes / modifications but I just want to make sure that the pathTokens system is still the way we want to go?

[vnugent]

I can fix this but I just want to make absolutely sure we don't want to resolve this at query time rather than at mod time?

We chatted about reads being far more frequent than writes / modifications but I just want to make sure that the pathTokens system is still the way we want to go?

Correct. We need to update pathToken, either iteratively or recursively, when doing updateArea(),

[saferthanhouses]

@vnugent Happy to look into this if it's available.

[zichongkao]

@saferthanhouses @CocoisBuggy I know it's been a while since we've updated this issue. Are either of you still open to taking it on?

[andrew-jp]

I'm new here/have no idea what I'm doing, but I've been working on this all day. What do you guys think of the general idea?

  updateArea()...
  ...
      const area = await this.areaModel.findOne(filter).session(session)
      if (area == null) {
        throw new Error('Area update error.  Reason: Area not found.')
      }

      const { areaName, description, shortCode, isDestination, isLeaf, isBoulder, lat, lng, experimentalAuthor } = document

  ...
      if (areaName != null) {
        const sanitizedName = sanitizeStrict(areaName)
        area.set({ area_name: sanitizedName })
        area.set({ pathTokens: area.pathTokens.slice(0, -1).push(sanitizedName) })

        if (area.children.length > 0) {
          await this.updatePathTokens(area.children, sanitizedName)
        }
      }

    ...
  async updatePathTokens (areaChildren: Types.ObjectId[], areaName: string, index: number = 2): Promise<void> {
    const session = await this.areaModel.startSession()

    for (const childId of areaChildren) {
      const filter = { _id: childId }

      const area = await this.areaModel.findOne(filter).session(session)
      if (area != null) {
        const newPath = area.pathTokens
        newPath[newPath.length - index] = areaName
        area.set({ pathTokens: newPath })

        if (area.children.length > 0) {
          await this.updatePathTokens(area.children, areaName, index + 1)
        }
        // save the changes
        await area.save()
      }
    }
  }

I really have no idea what I'm doing here, but I'm trying to figure it out. I would test it, but I believe I need API keys to edit anything even in a local env.

[vnugent]

@andrew-jp thanks for taking on this important issue. I think you're in the right direction.

Can you send me an email: viet at openbeta dot io ? I'll reply with API keys.

[andrew-jp]

My solution works! Just had to use a more JS/TS-like array copy. It looks good in testing so far, although recursion with queries/async operations involved is very expensive/slow. I'll see if I can improve the performance a bit.

Additionally, I'm trying to figure out if I need to use sessions in the "save" operation of the recursive function. Does the session protect/validate the Mongo transaction? I read some docs, but their purpose isn't totally clear to me. Any advice here would be helpful.

Central Wasatch - 20 (large) areas/3200 climbs - ~7.5s
Little Cottonwood Canyon - 59 areas/1800 climbs - ~4s
Both timed in real time - not the actual backend op.

[vnugent]

@andrew-jp great to hear!

In general it's not going to be perfomant when making individual db calls for each child.

In async updatePathTokens() I think you might be able to eliminate the for loop and multiple find() calls by either:

1. Calling mongoose populate() function to turn the array of area IDs into array of area objects.
2. Using the $in operator to get all area objects in 1 call

Similar code
https://github.com/OpenBeta/openbeta-graphql/blob/develop/src/db/utils/jobs/TreeUpdater.ts#L47