Exclude vertices based on edges

Question

I have a traditional social media graph where a user makes a post, other users comment on that post, and users can block other users. I'm trying to create a traversal that excludes comments where the commenting user has a block edge from the posting user (the posting user has blocked the commenting user, exclude their comments).

g.addV("user").as("poster")
.addV("post")
.addV("user").as("commenter")
.addV("comment")
.addE("post").from("poster").to("post")
.addE("comment").from("commenter").to("comment")
.addE("comment").from("comment").to("post")
.addE("block").from("poster").to("commenter")

This is as far as I got but doesn't compile:

g.V()
.hasLabel("comment")
.as("comment")
.not(
  __.in_("comment")
  .as("commenter")
  .select("comment")
  .where(
    __.out("comment")
    .in_("post")
    .out("block")
    .hasId(__.select("commentOwner").id()) // the poster is blocking the commenter
  )
)

This doesn't work but is the general idea. Exclude comments where the owner of the post is blocking the commenter. How can I construct this traversal?

PrashantUpadhyay PrashantUpadhyay · Accepted Answer · 2021-11-17T01:58:52

I modified your dataset to have 2 comments on the post. 1 from the blocked user and 1 from allowed user.

(Also changed labels to more clearly represent the action in edge labels)

g.addV("user").as("poster")
 .addV("post").as("post")
 .addV("user").as("commenter")
 .addV("user").property("name","user1").as("commenter1") # USERS

 .addV("comment").property("value", "commented by first user").as("comment")
 .addV("comment").property("value", "commented by second user").as("comment1") # COMMENTS

 .addE("posted").from("poster").to("post") 

 .addE("commentedBy").from("commenter").to("comment") 
 .addE("commentedBy").from("commenter1").to("comment1") 

 .addE("commentedOn").from("comment").to("post")
 .addE("commentedOn").from("comment1").to("post")

 .addE("block").from("poster").to("commenter")

Then this below query should do the trick:

g.V().
 hasLabel("user").as("poster").
 out("posted").
 in("commentedOn").as("comments").
 not(in("commentedBy").in("block").where(eq("poster"))).
 valueMap()

( It gives all the comments on the post by the user, from the commenters who are not blocked the user.)

Exclude vertices based on edges

1 Answers