CODEWITHSUNDEEP
gogo-gorm
Ari
Ari

Reputation: 6209

writing an API endpoint with multiple optional parameters

I'm playing around with building an API in Go, and it allows the user to search on 3 main points to find a "Job".

If a user doesn't provide any of these it defaults to returning ALL jobs in the table. My issue I feel is that the approach I am taking isn't scalable. There are 3 paramters, therefore ~9 possible combinations of what the user can provide. If I were to add a fourth, I would need to cover 16! searh combinations.

Here's what I have in my controller:

func (j *Jobs) List(c *client.Client, q string, l string, s string) error {

    // Return all jobs
    if q == "" && l == "" && s == "" {
        err := c.Database.Debug().Preload("Locations").Preload("Skills").Find(&j).Error //
        if err != nil {
            return err
        }
    }

    // Return based on query
    if q != "" && l == "" && s == "" {
        c.Database.Where("LOWER(title) like LOWER(?) OR LOWER(description) like LOWER(?)", "%"+q+"%", "%"+q+"%").Preload("Locations").Preload("Skills").Find(&j)
    }

    // return based on location
    if q == "" && l != "" && s == "" {
        c.Database.Preload("Skills").Preload("Locations").Joins("INNER JOIN job_location jl ON jl.job_id = jobs.id").Where("jl.location_name = ?", l).Find(&j)
    }

    // return based on skill
    if q == "" && l == "" && s != "" {
        c.Database.Preload("Skills").Preload("Locations").Joins("INNER JOIN job_skill js ON js.job_id = jobs.id").Where("js.skill_name = ?", s).Find(&j)
    }

    // return based on query + location
    if q != "" && l != "" && s == "" {
        c.Database.Preload("Locations").Preload("Skills").Joins("INNER JOIN job_location jl ON jl.job_id = jobs.id").Where("jl.location_name = ?", l).Where("LOWER(title) like LOWER(?) OR LOWER(description) like LOWER(?)", "%"+q+"%", "%"+q+"%").Find(&j)
    }

    // return based on query + skill
    if q != "" && l == "" && s != "" {
        c.Database.Preload("Locations").Preload("Skills").Joins("INNER JOIN job_skill js ON js.job_id = jobs.id").Where("js.skill_name = ?", s).Where("LOWER(title) like LOWER(?) OR LOWER(description) like LOWER(?)", "%"+q+"%", "%"+q+"%").Find(&j)
    }

    // return based on location + skill
    if q == "" && l != "" && s != "" {
        c.Database.Preload("Skills").Preload("Locations").Joins("INNER JOIN job_location jl ON jl.job_id = jobs.id").Joins("INNER JOIN job_skill js ON js.job_id = jobs.id").Where("jl.location_name = ?", l).Where("js.skill_name = ?", s).Find(&j)
    }

    // return based on query + skill + location
    if q != "" && l != "" && s != "" {
        c.Database.Preload("Locations").Preload("Skills").Joins("INNER JOIN job_location jl ON jl.job_id = jobs.id").Joins("INNER JOIN job_skill js ON js.job_id = jobs.id").Where("js.skill_name = ?", s).Where("jl.location_name = ?", l).Where("LOWER(title) like LOWER(?) OR LOWER(description) like LOWER(?)", "%"+q+"%", "%"+q+"%").Find(&j)
    }

    return nil
}

As you can see, with just 3 parameters it's a monsterous block of code. What are some ways I could improve this and make it more manageable as fields are added.

Upvotes: 0

Views: 233

Answers (1)

joelazar
joelazar

Reputation: 813

You can build up your query by creating a common part and later add the optional part to it, like this:

func (j *Jobs) List(c *client.Client, q string, l string, s string) error {
    query := c.Database.Debug().Preload("Locations").Preload("Skills")
    // return based on query
    if q != "" {
        query = query.Where("LOWER(title) like LOWER(?) OR LOWER(description) like LOWER(?)", "%"+q+"%", "%"+q+"%")
    }

    // return based on location
    if l != "" {
        query = query.Joins("INNER JOIN job_location jl ON jl.job_id = jobs.id").Where("jl.location_name = ?", l)
    }

    // return based on skill
    if s != "" {
        query = query.Joins("INNER JOIN job_skill js ON js.job_id = jobs.id").Where("js.skill_name = ?", s)
    }

    // Return all jobs
    return query.Find(&j).Error
}

Upvotes: 6

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