V2 Inspector2 Specification

V2Master | V2HighLevelDesign

Introduction

Development

Next Steps

1. Convert Edit Inspection Item model to a normal page

2. Convert Edit Inspection Record model to a normal page

3. Implement New Inspection Item

4. Implement New Inspection Record

5. Implement photos database table

6. Implement Photos List page (from home page?)

7. Implement ability to photos to an inspection record

8. Implement Show Photo Photos for Inspection Record

9. Implement Photos List for Inspection Record

10. Implement Download Algorithm (see below)
11. Implement Upload

12. Add Get Geolocation button to New & Edit Inspection Record screens

13. Implement upload photos

Main Menu

• Home -

• Inspection Records - Displays a list of Inspection Records

• Inspection Items - Displays a list of Inspection Items

• Synchronize - Displays counts of Inspection Records and Inspection Items. Buttons for Upload and Download data.

• Preferences -

• About Inspector - Displays Inspector version number and release date

• Contact Us

Screens

• Home

• Inspection Records (list)

• Inspection Record Detail

• Inspection Record New/Edit

• Inspection Items (list)

• Inspection Item Detail

• Inspection Item New/Edit

• Synchronize

• Statistics

• Preferences

• About Inspector

• Contact Us

Data Synchronization

Key data fields for synchronization:

• local_id - Primary key in the device (local) database

• local_is_dirty - If set to on-zero, then the record has been changed on the device

• local_is_conflict - If set, then the record has been change on the device and the server, and cannot be uploaded

• id - The server's primary key

• update_count - The server's update count. The device should never change this field

Download

• Data in JSON format is download from the server, from the following tables:

  • tags - Inspection Items

  • scans - Inspection Records

  • photos - Inspection Photos (not implemented yet)

Download Algorithm

For a single downloaded record:

  table = name of the table being processed
  new_record = record downloaded from server

  old_record = db.getById(table, record.id) -- Record from client device database

  if ( old_record == null ) {

    new_record.local_is_dirty = 0;
    new_record.local_is_conflict = 0
    db.insert(table, new_record) -- local_id is set by the database server

  } else {

    if ( new_record.update_count != old_record.update_count ) { // Server record was updated

      if ( old_record.local_is_dirty ) {

        db.updateById(table, old_record.id, {local_is_conflict: 1}) -- Set old_record.local_is_conflict = 1

      } else {

        record.local_is_conflict = 0
        db.updateById(table, new_record.id, new_record) -- Replace old_record with new_record (or delete & insert?)

      }
    }
  }

Data Upload

Upload Algorithm

1. Only upload records records that meet one the following conditions:

   1. local_is_dirty != 0

   2. id == null

2. Do not upload records where local_is_conflict != 0

To Do What are the responses from the server in the following cases:

1. Success

   1. Insert On a new record does the server respond with the new id value or path to access the new record?

   2. Update Does the server respond with the updated update_count. If not, can we always guarantee it is incremented by one

2. Conflict What is the response when the update_count of uploaded record doesn't not match that on the server

Possible responses to an insert/update:

• inserted: id updated: update_count conflict: an error code

For a single record to upload:

  table = name of the table being processed
  record = record to upload

  create a JSON string from the record, which does not include the following fields:
    local_id
    local_is_dirty
    local_is_conflict

  if ( record.id == null ) { // Insert a new record

    POST JSON to "http://{url}/{table}.json"

    record.id = id from server     -- how to get the new id from server?
    record.local_is_dirty = 0
    record.local_is_conflict = 0
    record.update_count = 1 (or 0?)

    db.updateByLocalId(record.local_id, record)

  } else { // Update existing record

    PUT JSON to "http://{url}/{record.id}/{table}.json

    if (response == OK) {

      -- do nothing or download record again to get new update_at value? 
      record.update_count = record.update_count + 1

      db.updateByLocalId(record.local_id, record)

    } else if ( response == conflict ) {

      db.updateById(record.id, {local_is_conflict: 1}) -- Set old_record.local_is_conflict = 1

    } else {

      report error

    }
  }