I am building an API to track student data using Scala, Akka HTTP, and Akka Actors.

But the API Routes below are not giving me the desired result.

The routes littlerock/admins and littlerock/schools/1 work as expected, but the rest show the error The requested resource could not be found.

I want the API to look for example like below.

All district admins - GET: http://localhost:8080/littlerock/admins

A school's details - GET: http://localhost:8080/littlerock/schools/{1}

All a school's students - GET: http://localhost:8080/littlerock/schools/{1}/students

A student's details - GET: http://localhost:8080/littlerock/schools/{1}/students/{1}

All the student's classmates - GET: http://localhost:8080/littlerock/schools/{1}/students/{1}/classmates

A student's classmate details - GET: http://localhost:8080/littlerock/schools/{1}/students/{1}/classmates/{1}

Could you help me fix the issue!

Thanks in advance!

The Routes code looks like below:

  val schoolRoutes: Route =
    pathPrefix("littlerock") {
    concat(

    pathPrefix("admins") {
      concat(
        pathEnd {
          concat(
            get {
              complete("District administrators.")
            })
        })
    },

    pathPrefix("schools") {
      concat(
        path(Segment) { name =>
          concat(
            pathEnd {
            get {
              rejectEmptyResponse {
                  complete("A school's details.")
              }
            }
            },
            path("students") {
              concat(
                pathEnd {
                  get {
                    rejectEmptyResponse {
                      complete("All students")
                    }
                  }
                },
                path(Segment) { name =>
                  concat(
                    pathEnd {
                    get {
                      rejectEmptyResponse {
                        complete("A student's details")
                      }
                    }},
                    path("classmates") {
                      concat(
                        pathEnd {
                          get {
                            rejectEmptyResponse {
                              complete("A student's classmates.")
                            }
                          }
                        },
                        path(Segment) { name =>
                          concat(
                            get {
                              rejectEmptyResponse {
                                complete("A classmate's details.")
                              }
                          })
                        }
                      )
                    }
                  )
                }
              )
            }
          )
      })
    }
  )}

I am building an API to track student data using Scala, Akka HTTP, and Akka Actors.

But the API Routes below are not giving me the desired result.

The routes littlerock/admins and littlerock/schools/1 work as expected, but the rest show the error The requested resource could not be found.

I want the API to look for example like below.

All district admins - GET: http://localhost:8080/littlerock/admins

A school's details - GET: http://localhost:8080/littlerock/schools/{1}

All a school's students - GET: http://localhost:8080/littlerock/schools/{1}/students

A student's details - GET: http://localhost:8080/littlerock/schools/{1}/students/{1}

All the student's classmates - GET: http://localhost:8080/littlerock/schools/{1}/students/{1}/classmates

A student's classmate details - GET: http://localhost:8080/littlerock/schools/{1}/students/{1}/classmates/{1}

Could you help me fix the issue!

Thanks in advance!

The Routes code looks like below:

  val schoolRoutes: Route =
    pathPrefix("littlerock") {
    concat(

    pathPrefix("admins") {
      concat(
        pathEnd {
          concat(
            get {
              complete("District administrators.")
            })
        })
    },

    pathPrefix("schools") {
      concat(
        path(Segment) { name =>
          concat(
            pathEnd {
            get {
              rejectEmptyResponse {
                  complete("A school's details.")
              }
            }
            },
            path("students") {
              concat(
                pathEnd {
                  get {
                    rejectEmptyResponse {
                      complete("All students")
                    }
                  }
                },
                path(Segment) { name =>
                  concat(
                    pathEnd {
                    get {
                      rejectEmptyResponse {
                        complete("A student's details")
                      }
                    }},
                    path("classmates") {
                      concat(
                        pathEnd {
                          get {
                            rejectEmptyResponse {
                              complete("A student's classmates.")
                            }
                          }
                        },
                        path(Segment) { name =>
                          concat(
                            get {
                              rejectEmptyResponse {
                                complete("A classmate's details.")
                              }
                          })
                        }
                      )
                    }
                  )
                }
              )
            }
          )
      })
    }
  )}

• scala
• akka
• akka-http

• 2 Look's good at first. Unless you've got a typo. I'd recommend to minimize the problem: write the minimum code required for littlerock/schools/{1}/students to work for instance and see what it does. – Gaël J Commented Nov 19, 2024 at 18:44

2 Answers 2

The reason is that path(...) matches against the full request path left, but you are using it to try to match prefixes of path, if you use pathPrefix(...) instead in the places where you do not want to match the full path up to the end that should sort it.

Like @johanandren suggested, I replaced all except the last path with pathPrefix.

And the code now works!

The Routes code now looks like below:

  val schoolRoutes: Route =
    pathPrefix("littlerock") {
    concat(

    pathPrefix("admins") {
      concat(
        pathEnd {
          concat(
            get {
              complete("District administrators.")
            })
        })
    },

    pathPrefix("schools") {
      concat(
        pathPrefix(Segment) { name =>
          concat(
            pathEnd {
            get {
              rejectEmptyResponse {
                  complete("A school's details.")
              }
            }
            },
            pathPrefix("students") {
              concat(
                pathEnd {
                  get {
                    rejectEmptyResponse {
                      complete("All students")
                    }
                  }
                },
                pathPrefix(Segment) { studentName =>
                  concat(
                    pathEnd {
                    get {
                      rejectEmptyResponse {
                        complete("A student's details")
                      }
                    }},
                    pathPrefix("classmates") {
                      concat(
                        pathEnd {
                          get {
                            rejectEmptyResponse {
                              complete("A student's classmates.")
                            }
                          }
                        },
                        path(Segment) { classmateName =>
                          concat(
                            get {
                              rejectEmptyResponse {
                                complete("A classmate's details.")
                              }
                          })
                        }
                      )
                    }
                  )
                }
              )
            }
          )
      })
    }
  )}