Add obs_tbl function to get OBSERVER tables (#35)

Project.toml

@@ -2,7 +2,7 @@ name = "HORIZONS"
 uuid = "5a3ac768-beb4-554a-9c98-3342fe3377f5"
 repo = "https://github.com/PerezHz/HORIZONS.jl.git"
 authors = ["Jorge A. Pérez Hernández", "Luis Eduardo Ramírez Montoya"]
-version = "0.4.1"
+version = "0.4.2"
 
 [deps]
 Base64 = "2a0f44e3-6c83-55bd-87e4-b1978d98bd5f"

src/HORIZONS.jl

@@ -7,7 +7,7 @@ module HORIZONS
 using HTTP, JSON, Base64, Dates
 using HTTP: Messages.Response
 
-export horizons, smb_spk, smb_spk_ele, vec_tbl, sbdb, sbradar
+export horizons, smb_spk, smb_spk_ele, vec_tbl, sbdb, sbradar, obs_tbl
 
 @doc raw"""
     horizons()
@@ -25,6 +25,7 @@ include("common.jl")
 include("horizonsapi.jl")
 include("sbdb.jl")
 include("sbradar.jl")
+include("obstbl.jl")
 
 function __init__()
 

src/obstbl.jl

@@ -0,0 +1,122 @@
+@doc raw"""
+    obs_tbl(COMMAND::ObjectName, START_TIME::StartStopTime, STOP_TIME::StartStopTime,
+            STEP_SIZE::StepSize; FILENAME::String = "", kwargs...) -> String
+
+Generate an observer table for object `COMMAND` from `START_TIME` to `STOP_TIME`
+with step `STEP_SIZE`. If `FILENAME` is empty, return the output as a `String`;
+otherwise, save the table to the corresponding file. For more information see
+[1], in particular the **Common Parameters** and **SPK File Parameters**
+sections; for a list of keyword arguments see the **Ephemeris-Specific
+Parameters** section.
+
+!!! reference
+    [1] https://ssd-api.jpl.nasa.gov/doc/horizons.html.
+
+# Examples
+```julia-repl
+# Date variables for start and stop times
+
+t_start = DateTime(2024,4,13)
+t_stop = Date(2024,4,14)
+
+# Step size (allowed types: Period, Int, String)
+
+δt = Hour(1) # 1 hour step size
+
+# Generate tables and save output to Voyager1.txt in current directory:
+
+julia> local_file = obs_tbl("Voyager 1", t_start, t_stop, δt;
+                            FILENAME = "Voyager1.txt", CENTER = "GBT", CSV_FORMAT = true)
+"Voyager1.txt"
+
+julia> isfile(local_file)
+true
+```
+"""
+function obs_tbl(COMMAND::ObjectName, START_TIME::StartStopTime, STOP_TIME::StartStopTime,
+                 STEP_SIZE::StepSize; FILENAME::String = "", CENTER::String = "Geocentric",
+                 COORD_TYPE::String = "GEODETIC", SITE_COORD::String = "0,0,0", QUANTITIES::String = "A",
+                 REF_SYSTEM::String = "ICRF", CAL_FORMAT::String = "CAL", CAL_TYPE::String = "MIXED",
+                 ANG_FORMAT::String = "HMS", APPARENT::String = "AIRLESS", TIME_DIGITS::String = "MINUTES",
+                 TIME_ZONE::String = "+00:00", RANGE_UNITS::String = "AU", SUPPRESS_RANGE_RATE::Bool = false,
+                 ELEV_CUT::Real = -90.0, SKIP_DAYLT::Bool = false, SOLAR_ELONG::NTuple{2,Real} = (0,180),
+                 AIRMASS::Real = 38.0, LHA_CUTOFF::Real = 0.0, ANG_RATE_CUTOFF::Real = 0.0,
+                 EXTRA_PREC::Bool = false, R_T_S_ONLY::Bool = false, CSV_FORMAT::Bool = false,
+                 MAKE_EPHEM::Bool = true, OBJ_DATA::Bool = true)
+
+    # Convert http parameters to String
+    command_str = jplstr(COMMAND)
+    start_time_str = jplstr(Dates.format(DateTime(START_TIME), JPL_DATE_FORMAT))
+    stop_time_str = jplstr(Dates.format(DateTime(STOP_TIME), JPL_DATE_FORMAT))
+    step_size_str = jplstr(STEP_SIZE)
+    center_str = jplstr(CENTER)
+    coord_type_str = jplstr(COORD_TYPE)
+    site_coord_str = jplstr(SITE_COORD)
+    quantities_str = jplstr(QUANTITIES)
+    ref_system_str = jplstr(REF_SYSTEM)
+    cal_format_str = jplstr(CAL_FORMAT)
+    cal_type_str = jplstr(CAL_TYPE)
+    ang_format_str = jplstr(ANG_FORMAT)
+    apparent_str = jplstr(APPARENT)
+    time_digits_str = jplstr(TIME_DIGITS)
+    time_zone_str = jplstr(TIME_ZONE)
+    range_units_str = jplstr(RANGE_UNITS)
+    suppress_range_rate_str = jplstr(SUPPRESS_RANGE_RATE)
+    elev_cut_str = jplstr(ELEV_CUT)
+    skip_daylt_str = jplstr(SKIP_DAYLT)
+    solar_elong_str = jplstr(join(SOLAR_ELONG, ','))
+    airmass_str = jplstr(AIRMASS)
+    lha_cutoff_str = jplstr(LHA_CUTOFF)
+    ang_rate_cutoff_str = jplstr(ANG_RATE_CUTOFF)
+    extra_prec_str = jplstr(EXTRA_PREC)
+    r_t_s_only_str = jplstr(R_T_S_ONLY)
+    csv_format_str = jplstr(CSV_FORMAT)
+    make_ephem_str = jplstr(MAKE_EPHEM)
+    obj_data_str = jplstr(OBJ_DATA)
+    # HTTP response code and text
+    code, text = jplapi(
+        HORIZONS_API_URL,
+        "COMMAND" => command_str,
+        "EPHEM_TYPE" => "OBSERVER",
+        "START_TIME" => start_time_str,
+        "STOP_TIME" => stop_time_str,
+        "STEP_SIZE" => step_size_str,
+        "CENTER" => center_str,
+        "COORD_TYPE" => coord_type_str,
+        "SITE_COORD" => site_coord_str,
+        "QUANTITIES" => quantities_str,
+        "REF_SYSTEM" => ref_system_str,
+        "CAL_FORMAT" => cal_format_str,
+        "CAL_TYPE" => cal_type_str,
+        "ANG_FORMAT" => ang_format_str,
+        "APPARENT" => apparent_str,
+        "TIME_DIGITS" => time_digits_str,
+        "TIME_ZONE" => time_zone_str,
+        "RANGE_UNITS" => range_units_str,
+        "SUPPRESS_RANGE_RATE" => suppress_range_rate_str,
+        "ELEV_CUT" => elev_cut_str,
+        "SKIP_DAYLT" => skip_daylt_str,
+        "SOLAR_ELONG" => solar_elong_str,
+        "AIRMASS" => airmass_str,
+        "LHA_CUTOFF" => lha_cutoff_str,
+        "ANG_RATE_CUTOFF" => ang_rate_cutoff_str,
+        "EXTRA_PREC" => extra_prec_str,
+        "R_T_S_ONLY" => r_t_s_only_str,
+        "CSV_FORMAT" => csv_format_str,
+        "MAKE_EPHEM" => make_ephem_str,
+        "OBJ_DATA" => obj_data_str
+    )
+    iszero(code) && return ""
+    # Parse JSON
+    dict = jsonparse(text)
+    # Return table as String
+    if isempty(FILENAME)
+        return dict["result"]
+    # Save table to FILENAME
+    else
+        open(FILENAME, "w") do file
+            write(file, dict["result"])
+        end
+        return FILENAME
+    end
+end

test/runtests.jl

@@ -123,4 +123,30 @@ end
     @test apophis_1["signature"] == apophis_2["signature"]
     @test all(map((x, y) -> x == y[1:end-1], apophis_1["data"], apophis_2["data"]))
     @test apophis_1["count"] == apophis_2["count"]
-end
+end
+
+@testset "Observer table generation: obs_tbl" begin
+    # Generate tables and save output to Voyager1.txt
+    t_start = DateTime(2024, 4, 13)
+    t_stop = Date(2024, 4, 14)
+    δt = Hour(1)
+    local_file = obs_tbl("Voyager 1", t_start, t_stop, δt; CSV_FORMAT = true,
+                         FILENAME = "Voyager1.txt", CENTER = "GBT")
+
+    @test isfile(local_file)
+
+    voyager1 = obs_tbl("Voyager 1", t_start, t_stop, δt; CSV_FORMAT = true,
+                       CENTER = "GBT")
+
+    x = readlines(local_file)
+    y = split(chomp(voyager1), "\n")
+
+    @test length(x) == length(y)
+    # Find lines that differ
+    diffinds = findall(x .!= y)
+    # The only lines that should differ start with "Ephemeris / API_USER" and
+    # contain time of retrieval.
+    @test all(startswith("Ephemeris / API_USER"), y[diffinds])
+
+    rm(local_file)
+end